diff --git a/vendor/github.com/google/btree/.travis.yml b/vendor/github.com/google/btree/.travis.yml
new file mode 100644
index 0000000..4f2ee4d
--- /dev/null
+++ b/vendor/github.com/google/btree/.travis.yml
@@ -0,0 +1 @@
+language: go
diff --git a/vendor/github.com/google/btree/LICENSE b/vendor/github.com/google/btree/LICENSE
new file mode 100644
index 0000000..d645695
--- /dev/null
+++ b/vendor/github.com/google/btree/LICENSE
@@ -0,0 +1,202 @@
+
+                                 Apache License
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+
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+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
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+      the terms of any separate license agreement you may have executed
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diff --git a/vendor/github.com/google/btree/README.md b/vendor/github.com/google/btree/README.md
new file mode 100644
index 0000000..6062a4d
--- /dev/null
+++ b/vendor/github.com/google/btree/README.md
@@ -0,0 +1,12 @@
+# BTree implementation for Go
+
+![Travis CI Build Status](https://api.travis-ci.org/google/btree.svg?branch=master)
+
+This package provides an in-memory B-Tree implementation for Go, useful as
+an ordered, mutable data structure.
+
+The API is based off of the wonderful
+http://godoc.org/github.com/petar/GoLLRB/llrb, and is meant to allow btree to
+act as a drop-in replacement for gollrb trees.
+
+See http://godoc.org/github.com/google/btree for documentation.
diff --git a/vendor/github.com/google/btree/btree.go b/vendor/github.com/google/btree/btree.go
new file mode 100644
index 0000000..6ff062f
--- /dev/null
+++ b/vendor/github.com/google/btree/btree.go
@@ -0,0 +1,890 @@
+// Copyright 2014 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package btree implements in-memory B-Trees of arbitrary degree.
+//
+// btree implements an in-memory B-Tree for use as an ordered data structure.
+// It is not meant for persistent storage solutions.
+//
+// It has a flatter structure than an equivalent red-black or other binary tree,
+// which in some cases yields better memory usage and/or performance.
+// See some discussion on the matter here:
+//   http://google-opensource.blogspot.com/2013/01/c-containers-that-save-memory-and-time.html
+// Note, though, that this project is in no way related to the C++ B-Tree
+// implementation written about there.
+//
+// Within this tree, each node contains a slice of items and a (possibly nil)
+// slice of children.  For basic numeric values or raw structs, this can cause
+// efficiency differences when compared to equivalent C++ template code that
+// stores values in arrays within the node:
+//   * Due to the overhead of storing values as interfaces (each
+//     value needs to be stored as the value itself, then 2 words for the
+//     interface pointing to that value and its type), resulting in higher
+//     memory use.
+//   * Since interfaces can point to values anywhere in memory, values are
+//     most likely not stored in contiguous blocks, resulting in a higher
+//     number of cache misses.
+// These issues don't tend to matter, though, when working with strings or other
+// heap-allocated structures, since C++-equivalent structures also must store
+// pointers and also distribute their values across the heap.
+//
+// This implementation is designed to be a drop-in replacement to gollrb.LLRB
+// trees, (http://github.com/petar/gollrb), an excellent and probably the most
+// widely used ordered tree implementation in the Go ecosystem currently.
+// Its functions, therefore, exactly mirror those of
+// llrb.LLRB where possible.  Unlike gollrb, though, we currently don't
+// support storing multiple equivalent values.
+package btree
+
+import (
+	"fmt"
+	"io"
+	"sort"
+	"strings"
+	"sync"
+)
+
+// Item represents a single object in the tree.
+type Item interface {
+	// Less tests whether the current item is less than the given argument.
+	//
+	// This must provide a strict weak ordering.
+	// If !a.Less(b) && !b.Less(a), we treat this to mean a == b (i.e. we can only
+	// hold one of either a or b in the tree).
+	Less(than Item) bool
+}
+
+const (
+	DefaultFreeListSize = 32
+)
+
+var (
+	nilItems    = make(items, 16)
+	nilChildren = make(children, 16)
+)
+
+// FreeList represents a free list of btree nodes. By default each
+// BTree has its own FreeList, but multiple BTrees can share the same
+// FreeList.
+// Two Btrees using the same freelist are safe for concurrent write access.
+type FreeList struct {
+	mu       sync.Mutex
+	freelist []*node
+}
+
+// NewFreeList creates a new free list.
+// size is the maximum size of the returned free list.
+func NewFreeList(size int) *FreeList {
+	return &FreeList{freelist: make([]*node, 0, size)}
+}
+
+func (f *FreeList) newNode() (n *node) {
+	f.mu.Lock()
+	index := len(f.freelist) - 1
+	if index < 0 {
+		f.mu.Unlock()
+		return new(node)
+	}
+	n = f.freelist[index]
+	f.freelist[index] = nil
+	f.freelist = f.freelist[:index]
+	f.mu.Unlock()
+	return
+}
+
+// freeNode adds the given node to the list, returning true if it was added
+// and false if it was discarded.
+func (f *FreeList) freeNode(n *node) (out bool) {
+	f.mu.Lock()
+	if len(f.freelist) < cap(f.freelist) {
+		f.freelist = append(f.freelist, n)
+		out = true
+	}
+	f.mu.Unlock()
+	return
+}
+
+// ItemIterator allows callers of Ascend* to iterate in-order over portions of
+// the tree.  When this function returns false, iteration will stop and the
+// associated Ascend* function will immediately return.
+type ItemIterator func(i Item) bool
+
+// New creates a new B-Tree with the given degree.
+//
+// New(2), for example, will create a 2-3-4 tree (each node contains 1-3 items
+// and 2-4 children).
+func New(degree int) *BTree {
+	return NewWithFreeList(degree, NewFreeList(DefaultFreeListSize))
+}
+
+// NewWithFreeList creates a new B-Tree that uses the given node free list.
+func NewWithFreeList(degree int, f *FreeList) *BTree {
+	if degree <= 1 {
+		panic("bad degree")
+	}
+	return &BTree{
+		degree: degree,
+		cow:    &copyOnWriteContext{freelist: f},
+	}
+}
+
+// items stores items in a node.
+type items []Item
+
+// insertAt inserts a value into the given index, pushing all subsequent values
+// forward.
+func (s *items) insertAt(index int, item Item) {
+	*s = append(*s, nil)
+	if index < len(*s) {
+		copy((*s)[index+1:], (*s)[index:])
+	}
+	(*s)[index] = item
+}
+
+// removeAt removes a value at a given index, pulling all subsequent values
+// back.
+func (s *items) removeAt(index int) Item {
+	item := (*s)[index]
+	copy((*s)[index:], (*s)[index+1:])
+	(*s)[len(*s)-1] = nil
+	*s = (*s)[:len(*s)-1]
+	return item
+}
+
+// pop removes and returns the last element in the list.
+func (s *items) pop() (out Item) {
+	index := len(*s) - 1
+	out = (*s)[index]
+	(*s)[index] = nil
+	*s = (*s)[:index]
+	return
+}
+
+// truncate truncates this instance at index so that it contains only the
+// first index items. index must be less than or equal to length.
+func (s *items) truncate(index int) {
+	var toClear items
+	*s, toClear = (*s)[:index], (*s)[index:]
+	for len(toClear) > 0 {
+		toClear = toClear[copy(toClear, nilItems):]
+	}
+}
+
+// find returns the index where the given item should be inserted into this
+// list.  'found' is true if the item already exists in the list at the given
+// index.
+func (s items) find(item Item) (index int, found bool) {
+	i := sort.Search(len(s), func(i int) bool {
+		return item.Less(s[i])
+	})
+	if i > 0 && !s[i-1].Less(item) {
+		return i - 1, true
+	}
+	return i, false
+}
+
+// children stores child nodes in a node.
+type children []*node
+
+// insertAt inserts a value into the given index, pushing all subsequent values
+// forward.
+func (s *children) insertAt(index int, n *node) {
+	*s = append(*s, nil)
+	if index < len(*s) {
+		copy((*s)[index+1:], (*s)[index:])
+	}
+	(*s)[index] = n
+}
+
+// removeAt removes a value at a given index, pulling all subsequent values
+// back.
+func (s *children) removeAt(index int) *node {
+	n := (*s)[index]
+	copy((*s)[index:], (*s)[index+1:])
+	(*s)[len(*s)-1] = nil
+	*s = (*s)[:len(*s)-1]
+	return n
+}
+
+// pop removes and returns the last element in the list.
+func (s *children) pop() (out *node) {
+	index := len(*s) - 1
+	out = (*s)[index]
+	(*s)[index] = nil
+	*s = (*s)[:index]
+	return
+}
+
+// truncate truncates this instance at index so that it contains only the
+// first index children. index must be less than or equal to length.
+func (s *children) truncate(index int) {
+	var toClear children
+	*s, toClear = (*s)[:index], (*s)[index:]
+	for len(toClear) > 0 {
+		toClear = toClear[copy(toClear, nilChildren):]
+	}
+}
+
+// node is an internal node in a tree.
+//
+// It must at all times maintain the invariant that either
+//   * len(children) == 0, len(items) unconstrained
+//   * len(children) == len(items) + 1
+type node struct {
+	items    items
+	children children
+	cow      *copyOnWriteContext
+}
+
+func (n *node) mutableFor(cow *copyOnWriteContext) *node {
+	if n.cow == cow {
+		return n
+	}
+	out := cow.newNode()
+	if cap(out.items) >= len(n.items) {
+		out.items = out.items[:len(n.items)]
+	} else {
+		out.items = make(items, len(n.items), cap(n.items))
+	}
+	copy(out.items, n.items)
+	// Copy children
+	if cap(out.children) >= len(n.children) {
+		out.children = out.children[:len(n.children)]
+	} else {
+		out.children = make(children, len(n.children), cap(n.children))
+	}
+	copy(out.children, n.children)
+	return out
+}
+
+func (n *node) mutableChild(i int) *node {
+	c := n.children[i].mutableFor(n.cow)
+	n.children[i] = c
+	return c
+}
+
+// split splits the given node at the given index.  The current node shrinks,
+// and this function returns the item that existed at that index and a new node
+// containing all items/children after it.
+func (n *node) split(i int) (Item, *node) {
+	item := n.items[i]
+	next := n.cow.newNode()
+	next.items = append(next.items, n.items[i+1:]...)
+	n.items.truncate(i)
+	if len(n.children) > 0 {
+		next.children = append(next.children, n.children[i+1:]...)
+		n.children.truncate(i + 1)
+	}
+	return item, next
+}
+
+// maybeSplitChild checks if a child should be split, and if so splits it.
+// Returns whether or not a split occurred.
+func (n *node) maybeSplitChild(i, maxItems int) bool {
+	if len(n.children[i].items) < maxItems {
+		return false
+	}
+	first := n.mutableChild(i)
+	item, second := first.split(maxItems / 2)
+	n.items.insertAt(i, item)
+	n.children.insertAt(i+1, second)
+	return true
+}
+
+// insert inserts an item into the subtree rooted at this node, making sure
+// no nodes in the subtree exceed maxItems items.  Should an equivalent item be
+// be found/replaced by insert, it will be returned.
+func (n *node) insert(item Item, maxItems int) Item {
+	i, found := n.items.find(item)
+	if found {
+		out := n.items[i]
+		n.items[i] = item
+		return out
+	}
+	if len(n.children) == 0 {
+		n.items.insertAt(i, item)
+		return nil
+	}
+	if n.maybeSplitChild(i, maxItems) {
+		inTree := n.items[i]
+		switch {
+		case item.Less(inTree):
+			// no change, we want first split node
+		case inTree.Less(item):
+			i++ // we want second split node
+		default:
+			out := n.items[i]
+			n.items[i] = item
+			return out
+		}
+	}
+	return n.mutableChild(i).insert(item, maxItems)
+}
+
+// get finds the given key in the subtree and returns it.
+func (n *node) get(key Item) Item {
+	i, found := n.items.find(key)
+	if found {
+		return n.items[i]
+	} else if len(n.children) > 0 {
+		return n.children[i].get(key)
+	}
+	return nil
+}
+
+// min returns the first item in the subtree.
+func min(n *node) Item {
+	if n == nil {
+		return nil
+	}
+	for len(n.children) > 0 {
+		n = n.children[0]
+	}
+	if len(n.items) == 0 {
+		return nil
+	}
+	return n.items[0]
+}
+
+// max returns the last item in the subtree.
+func max(n *node) Item {
+	if n == nil {
+		return nil
+	}
+	for len(n.children) > 0 {
+		n = n.children[len(n.children)-1]
+	}
+	if len(n.items) == 0 {
+		return nil
+	}
+	return n.items[len(n.items)-1]
+}
+
+// toRemove details what item to remove in a node.remove call.
+type toRemove int
+
+const (
+	removeItem toRemove = iota // removes the given item
+	removeMin                  // removes smallest item in the subtree
+	removeMax                  // removes largest item in the subtree
+)
+
+// remove removes an item from the subtree rooted at this node.
+func (n *node) remove(item Item, minItems int, typ toRemove) Item {
+	var i int
+	var found bool
+	switch typ {
+	case removeMax:
+		if len(n.children) == 0 {
+			return n.items.pop()
+		}
+		i = len(n.items)
+	case removeMin:
+		if len(n.children) == 0 {
+			return n.items.removeAt(0)
+		}
+		i = 0
+	case removeItem:
+		i, found = n.items.find(item)
+		if len(n.children) == 0 {
+			if found {
+				return n.items.removeAt(i)
+			}
+			return nil
+		}
+	default:
+		panic("invalid type")
+	}
+	// If we get to here, we have children.
+	if len(n.children[i].items) <= minItems {
+		return n.growChildAndRemove(i, item, minItems, typ)
+	}
+	child := n.mutableChild(i)
+	// Either we had enough items to begin with, or we've done some
+	// merging/stealing, because we've got enough now and we're ready to return
+	// stuff.
+	if found {
+		// The item exists at index 'i', and the child we've selected can give us a
+		// predecessor, since if we've gotten here it's got > minItems items in it.
+		out := n.items[i]
+		// We use our special-case 'remove' call with typ=maxItem to pull the
+		// predecessor of item i (the rightmost leaf of our immediate left child)
+		// and set it into where we pulled the item from.
+		n.items[i] = child.remove(nil, minItems, removeMax)
+		return out
+	}
+	// Final recursive call.  Once we're here, we know that the item isn't in this
+	// node and that the child is big enough to remove from.
+	return child.remove(item, minItems, typ)
+}
+
+// growChildAndRemove grows child 'i' to make sure it's possible to remove an
+// item from it while keeping it at minItems, then calls remove to actually
+// remove it.
+//
+// Most documentation says we have to do two sets of special casing:
+//   1) item is in this node
+//   2) item is in child
+// In both cases, we need to handle the two subcases:
+//   A) node has enough values that it can spare one
+//   B) node doesn't have enough values
+// For the latter, we have to check:
+//   a) left sibling has node to spare
+//   b) right sibling has node to spare
+//   c) we must merge
+// To simplify our code here, we handle cases #1 and #2 the same:
+// If a node doesn't have enough items, we make sure it does (using a,b,c).
+// We then simply redo our remove call, and the second time (regardless of
+// whether we're in case 1 or 2), we'll have enough items and can guarantee
+// that we hit case A.
+func (n *node) growChildAndRemove(i int, item Item, minItems int, typ toRemove) Item {
+	if i > 0 && len(n.children[i-1].items) > minItems {
+		// Steal from left child
+		child := n.mutableChild(i)
+		stealFrom := n.mutableChild(i - 1)
+		stolenItem := stealFrom.items.pop()
+		child.items.insertAt(0, n.items[i-1])
+		n.items[i-1] = stolenItem
+		if len(stealFrom.children) > 0 {
+			child.children.insertAt(0, stealFrom.children.pop())
+		}
+	} else if i < len(n.items) && len(n.children[i+1].items) > minItems {
+		// steal from right child
+		child := n.mutableChild(i)
+		stealFrom := n.mutableChild(i + 1)
+		stolenItem := stealFrom.items.removeAt(0)
+		child.items = append(child.items, n.items[i])
+		n.items[i] = stolenItem
+		if len(stealFrom.children) > 0 {
+			child.children = append(child.children, stealFrom.children.removeAt(0))
+		}
+	} else {
+		if i >= len(n.items) {
+			i--
+		}
+		child := n.mutableChild(i)
+		// merge with right child
+		mergeItem := n.items.removeAt(i)
+		mergeChild := n.children.removeAt(i + 1)
+		child.items = append(child.items, mergeItem)
+		child.items = append(child.items, mergeChild.items...)
+		child.children = append(child.children, mergeChild.children...)
+		n.cow.freeNode(mergeChild)
+	}
+	return n.remove(item, minItems, typ)
+}
+
+type direction int
+
+const (
+	descend = direction(-1)
+	ascend  = direction(+1)
+)
+
+// iterate provides a simple method for iterating over elements in the tree.
+//
+// When ascending, the 'start' should be less than 'stop' and when descending,
+// the 'start' should be greater than 'stop'. Setting 'includeStart' to true
+// will force the iterator to include the first item when it equals 'start',
+// thus creating a "greaterOrEqual" or "lessThanEqual" rather than just a
+// "greaterThan" or "lessThan" queries.
+func (n *node) iterate(dir direction, start, stop Item, includeStart bool, hit bool, iter ItemIterator) (bool, bool) {
+	var ok, found bool
+	var index int
+	switch dir {
+	case ascend:
+		if start != nil {
+			index, _ = n.items.find(start)
+		}
+		for i := index; i < len(n.items); i++ {
+			if len(n.children) > 0 {
+				if hit, ok = n.children[i].iterate(dir, start, stop, includeStart, hit, iter); !ok {
+					return hit, false
+				}
+			}
+			if !includeStart && !hit && start != nil && !start.Less(n.items[i]) {
+				hit = true
+				continue
+			}
+			hit = true
+			if stop != nil && !n.items[i].Less(stop) {
+				return hit, false
+			}
+			if !iter(n.items[i]) {
+				return hit, false
+			}
+		}
+		if len(n.children) > 0 {
+			if hit, ok = n.children[len(n.children)-1].iterate(dir, start, stop, includeStart, hit, iter); !ok {
+				return hit, false
+			}
+		}
+	case descend:
+		if start != nil {
+			index, found = n.items.find(start)
+			if !found {
+				index = index - 1
+			}
+		} else {
+			index = len(n.items) - 1
+		}
+		for i := index; i >= 0; i-- {
+			if start != nil && !n.items[i].Less(start) {
+				if !includeStart || hit || start.Less(n.items[i]) {
+					continue
+				}
+			}
+			if len(n.children) > 0 {
+				if hit, ok = n.children[i+1].iterate(dir, start, stop, includeStart, hit, iter); !ok {
+					return hit, false
+				}
+			}
+			if stop != nil && !stop.Less(n.items[i]) {
+				return hit, false //	continue
+			}
+			hit = true
+			if !iter(n.items[i]) {
+				return hit, false
+			}
+		}
+		if len(n.children) > 0 {
+			if hit, ok = n.children[0].iterate(dir, start, stop, includeStart, hit, iter); !ok {
+				return hit, false
+			}
+		}
+	}
+	return hit, true
+}
+
+// Used for testing/debugging purposes.
+func (n *node) print(w io.Writer, level int) {
+	fmt.Fprintf(w, "%sNODE:%v\n", strings.Repeat("  ", level), n.items)
+	for _, c := range n.children {
+		c.print(w, level+1)
+	}
+}
+
+// BTree is an implementation of a B-Tree.
+//
+// BTree stores Item instances in an ordered structure, allowing easy insertion,
+// removal, and iteration.
+//
+// Write operations are not safe for concurrent mutation by multiple
+// goroutines, but Read operations are.
+type BTree struct {
+	degree int
+	length int
+	root   *node
+	cow    *copyOnWriteContext
+}
+
+// copyOnWriteContext pointers determine node ownership... a tree with a write
+// context equivalent to a node's write context is allowed to modify that node.
+// A tree whose write context does not match a node's is not allowed to modify
+// it, and must create a new, writable copy (IE: it's a Clone).
+//
+// When doing any write operation, we maintain the invariant that the current
+// node's context is equal to the context of the tree that requested the write.
+// We do this by, before we descend into any node, creating a copy with the
+// correct context if the contexts don't match.
+//
+// Since the node we're currently visiting on any write has the requesting
+// tree's context, that node is modifiable in place.  Children of that node may
+// not share context, but before we descend into them, we'll make a mutable
+// copy.
+type copyOnWriteContext struct {
+	freelist *FreeList
+}
+
+// Clone clones the btree, lazily.  Clone should not be called concurrently,
+// but the original tree (t) and the new tree (t2) can be used concurrently
+// once the Clone call completes.
+//
+// The internal tree structure of b is marked read-only and shared between t and
+// t2.  Writes to both t and t2 use copy-on-write logic, creating new nodes
+// whenever one of b's original nodes would have been modified.  Read operations
+// should have no performance degredation.  Write operations for both t and t2
+// will initially experience minor slow-downs caused by additional allocs and
+// copies due to the aforementioned copy-on-write logic, but should converge to
+// the original performance characteristics of the original tree.
+func (t *BTree) Clone() (t2 *BTree) {
+	// Create two entirely new copy-on-write contexts.
+	// This operation effectively creates three trees:
+	//   the original, shared nodes (old b.cow)
+	//   the new b.cow nodes
+	//   the new out.cow nodes
+	cow1, cow2 := *t.cow, *t.cow
+	out := *t
+	t.cow = &cow1
+	out.cow = &cow2
+	return &out
+}
+
+// maxItems returns the max number of items to allow per node.
+func (t *BTree) maxItems() int {
+	return t.degree*2 - 1
+}
+
+// minItems returns the min number of items to allow per node (ignored for the
+// root node).
+func (t *BTree) minItems() int {
+	return t.degree - 1
+}
+
+func (c *copyOnWriteContext) newNode() (n *node) {
+	n = c.freelist.newNode()
+	n.cow = c
+	return
+}
+
+type freeType int
+
+const (
+	ftFreelistFull freeType = iota // node was freed (available for GC, not stored in freelist)
+	ftStored                       // node was stored in the freelist for later use
+	ftNotOwned                     // node was ignored by COW, since it's owned by another one
+)
+
+// freeNode frees a node within a given COW context, if it's owned by that
+// context.  It returns what happened to the node (see freeType const
+// documentation).
+func (c *copyOnWriteContext) freeNode(n *node) freeType {
+	if n.cow == c {
+		// clear to allow GC
+		n.items.truncate(0)
+		n.children.truncate(0)
+		n.cow = nil
+		if c.freelist.freeNode(n) {
+			return ftStored
+		} else {
+			return ftFreelistFull
+		}
+	} else {
+		return ftNotOwned
+	}
+}
+
+// ReplaceOrInsert adds the given item to the tree.  If an item in the tree
+// already equals the given one, it is removed from the tree and returned.
+// Otherwise, nil is returned.
+//
+// nil cannot be added to the tree (will panic).
+func (t *BTree) ReplaceOrInsert(item Item) Item {
+	if item == nil {
+		panic("nil item being added to BTree")
+	}
+	if t.root == nil {
+		t.root = t.cow.newNode()
+		t.root.items = append(t.root.items, item)
+		t.length++
+		return nil
+	} else {
+		t.root = t.root.mutableFor(t.cow)
+		if len(t.root.items) >= t.maxItems() {
+			item2, second := t.root.split(t.maxItems() / 2)
+			oldroot := t.root
+			t.root = t.cow.newNode()
+			t.root.items = append(t.root.items, item2)
+			t.root.children = append(t.root.children, oldroot, second)
+		}
+	}
+	out := t.root.insert(item, t.maxItems())
+	if out == nil {
+		t.length++
+	}
+	return out
+}
+
+// Delete removes an item equal to the passed in item from the tree, returning
+// it.  If no such item exists, returns nil.
+func (t *BTree) Delete(item Item) Item {
+	return t.deleteItem(item, removeItem)
+}
+
+// DeleteMin removes the smallest item in the tree and returns it.
+// If no such item exists, returns nil.
+func (t *BTree) DeleteMin() Item {
+	return t.deleteItem(nil, removeMin)
+}
+
+// DeleteMax removes the largest item in the tree and returns it.
+// If no such item exists, returns nil.
+func (t *BTree) DeleteMax() Item {
+	return t.deleteItem(nil, removeMax)
+}
+
+func (t *BTree) deleteItem(item Item, typ toRemove) Item {
+	if t.root == nil || len(t.root.items) == 0 {
+		return nil
+	}
+	t.root = t.root.mutableFor(t.cow)
+	out := t.root.remove(item, t.minItems(), typ)
+	if len(t.root.items) == 0 && len(t.root.children) > 0 {
+		oldroot := t.root
+		t.root = t.root.children[0]
+		t.cow.freeNode(oldroot)
+	}
+	if out != nil {
+		t.length--
+	}
+	return out
+}
+
+// AscendRange calls the iterator for every value in the tree within the range
+// [greaterOrEqual, lessThan), until iterator returns false.
+func (t *BTree) AscendRange(greaterOrEqual, lessThan Item, iterator ItemIterator) {
+	if t.root == nil {
+		return
+	}
+	t.root.iterate(ascend, greaterOrEqual, lessThan, true, false, iterator)
+}
+
+// AscendLessThan calls the iterator for every value in the tree within the range
+// [first, pivot), until iterator returns false.
+func (t *BTree) AscendLessThan(pivot Item, iterator ItemIterator) {
+	if t.root == nil {
+		return
+	}
+	t.root.iterate(ascend, nil, pivot, false, false, iterator)
+}
+
+// AscendGreaterOrEqual calls the iterator for every value in the tree within
+// the range [pivot, last], until iterator returns false.
+func (t *BTree) AscendGreaterOrEqual(pivot Item, iterator ItemIterator) {
+	if t.root == nil {
+		return
+	}
+	t.root.iterate(ascend, pivot, nil, true, false, iterator)
+}
+
+// Ascend calls the iterator for every value in the tree within the range
+// [first, last], until iterator returns false.
+func (t *BTree) Ascend(iterator ItemIterator) {
+	if t.root == nil {
+		return
+	}
+	t.root.iterate(ascend, nil, nil, false, false, iterator)
+}
+
+// DescendRange calls the iterator for every value in the tree within the range
+// [lessOrEqual, greaterThan), until iterator returns false.
+func (t *BTree) DescendRange(lessOrEqual, greaterThan Item, iterator ItemIterator) {
+	if t.root == nil {
+		return
+	}
+	t.root.iterate(descend, lessOrEqual, greaterThan, true, false, iterator)
+}
+
+// DescendLessOrEqual calls the iterator for every value in the tree within the range
+// [pivot, first], until iterator returns false.
+func (t *BTree) DescendLessOrEqual(pivot Item, iterator ItemIterator) {
+	if t.root == nil {
+		return
+	}
+	t.root.iterate(descend, pivot, nil, true, false, iterator)
+}
+
+// DescendGreaterThan calls the iterator for every value in the tree within
+// the range (pivot, last], until iterator returns false.
+func (t *BTree) DescendGreaterThan(pivot Item, iterator ItemIterator) {
+	if t.root == nil {
+		return
+	}
+	t.root.iterate(descend, nil, pivot, false, false, iterator)
+}
+
+// Descend calls the iterator for every value in the tree within the range
+// [last, first], until iterator returns false.
+func (t *BTree) Descend(iterator ItemIterator) {
+	if t.root == nil {
+		return
+	}
+	t.root.iterate(descend, nil, nil, false, false, iterator)
+}
+
+// Get looks for the key item in the tree, returning it.  It returns nil if
+// unable to find that item.
+func (t *BTree) Get(key Item) Item {
+	if t.root == nil {
+		return nil
+	}
+	return t.root.get(key)
+}
+
+// Min returns the smallest item in the tree, or nil if the tree is empty.
+func (t *BTree) Min() Item {
+	return min(t.root)
+}
+
+// Max returns the largest item in the tree, or nil if the tree is empty.
+func (t *BTree) Max() Item {
+	return max(t.root)
+}
+
+// Has returns true if the given key is in the tree.
+func (t *BTree) Has(key Item) bool {
+	return t.Get(key) != nil
+}
+
+// Len returns the number of items currently in the tree.
+func (t *BTree) Len() int {
+	return t.length
+}
+
+// Clear removes all items from the btree.  If addNodesToFreelist is true,
+// t's nodes are added to its freelist as part of this call, until the freelist
+// is full.  Otherwise, the root node is simply dereferenced and the subtree
+// left to Go's normal GC processes.
+//
+// This can be much faster
+// than calling Delete on all elements, because that requires finding/removing
+// each element in the tree and updating the tree accordingly.  It also is
+// somewhat faster than creating a new tree to replace the old one, because
+// nodes from the old tree are reclaimed into the freelist for use by the new
+// one, instead of being lost to the garbage collector.
+//
+// This call takes:
+//   O(1): when addNodesToFreelist is false, this is a single operation.
+//   O(1): when the freelist is already full, it breaks out immediately
+//   O(freelist size):  when the freelist is empty and the nodes are all owned
+//       by this tree, nodes are added to the freelist until full.
+//   O(tree size):  when all nodes are owned by another tree, all nodes are
+//       iterated over looking for nodes to add to the freelist, and due to
+//       ownership, none are.
+func (t *BTree) Clear(addNodesToFreelist bool) {
+	if t.root != nil && addNodesToFreelist {
+		t.root.reset(t.cow)
+	}
+	t.root, t.length = nil, 0
+}
+
+// reset returns a subtree to the freelist.  It breaks out immediately if the
+// freelist is full, since the only benefit of iterating is to fill that
+// freelist up.  Returns true if parent reset call should continue.
+func (n *node) reset(c *copyOnWriteContext) bool {
+	for _, child := range n.children {
+		if !child.reset(c) {
+			return false
+		}
+	}
+	return c.freeNode(n) != ftFreelistFull
+}
+
+// Int implements the Item interface for integers.
+type Int int
+
+// Less returns true if int(a) < int(b).
+func (a Int) Less(b Item) bool {
+	return a < b.(Int)
+}
diff --git a/vendor/github.com/google/btree/btree_mem.go b/vendor/github.com/google/btree/btree_mem.go
new file mode 100644
index 0000000..cb95b7f
--- /dev/null
+++ b/vendor/github.com/google/btree/btree_mem.go
@@ -0,0 +1,76 @@
+// Copyright 2014 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build ignore
+
+// This binary compares memory usage between btree and gollrb.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"math/rand"
+	"runtime"
+	"time"
+
+	"github.com/google/btree"
+	"github.com/petar/GoLLRB/llrb"
+)
+
+var (
+	size   = flag.Int("size", 1000000, "size of the tree to build")
+	degree = flag.Int("degree", 8, "degree of btree")
+	gollrb = flag.Bool("llrb", false, "use llrb instead of btree")
+)
+
+func main() {
+	flag.Parse()
+	vals := rand.Perm(*size)
+	var t, v interface{}
+	v = vals
+	var stats runtime.MemStats
+	for i := 0; i < 10; i++ {
+		runtime.GC()
+	}
+	fmt.Println("-------- BEFORE ----------")
+	runtime.ReadMemStats(&stats)
+	fmt.Printf("%+v\n", stats)
+	start := time.Now()
+	if *gollrb {
+		tr := llrb.New()
+		for _, v := range vals {
+			tr.ReplaceOrInsert(llrb.Int(v))
+		}
+		t = tr // keep it around
+	} else {
+		tr := btree.New(*degree)
+		for _, v := range vals {
+			tr.ReplaceOrInsert(btree.Int(v))
+		}
+		t = tr // keep it around
+	}
+	fmt.Printf("%v inserts in %v\n", *size, time.Since(start))
+	fmt.Println("-------- AFTER ----------")
+	runtime.ReadMemStats(&stats)
+	fmt.Printf("%+v\n", stats)
+	for i := 0; i < 10; i++ {
+		runtime.GC()
+	}
+	fmt.Println("-------- AFTER GC ----------")
+	runtime.ReadMemStats(&stats)
+	fmt.Printf("%+v\n", stats)
+	if t == v {
+		fmt.Println("to make sure vals and tree aren't GC'd")
+	}
+}
diff --git a/vendor/github.com/google/gofuzz/.travis.yml b/vendor/github.com/google/gofuzz/.travis.yml
new file mode 100644
index 0000000..f8684d9
--- /dev/null
+++ b/vendor/github.com/google/gofuzz/.travis.yml
@@ -0,0 +1,13 @@
+language: go
+
+go:
+  - 1.4
+  - 1.3
+  - 1.2
+  - tip
+
+install:
+  - if ! go get code.google.com/p/go.tools/cmd/cover; then go get golang.org/x/tools/cmd/cover; fi
+
+script:
+  - go test -cover
diff --git a/vendor/github.com/google/gofuzz/CONTRIBUTING.md b/vendor/github.com/google/gofuzz/CONTRIBUTING.md
new file mode 100644
index 0000000..51cf5cd
--- /dev/null
+++ b/vendor/github.com/google/gofuzz/CONTRIBUTING.md
@@ -0,0 +1,67 @@
+# How to contribute #
+
+We'd love to accept your patches and contributions to this project.  There are
+a just a few small guidelines you need to follow.
+
+
+## Contributor License Agreement ##
+
+Contributions to any Google project must be accompanied by a Contributor
+License Agreement.  This is not a copyright **assignment**, it simply gives
+Google permission to use and redistribute your contributions as part of the
+project.
+
+  * If you are an individual writing original source code and you're sure you
+    own the intellectual property, then you'll need to sign an [individual
+    CLA][].
+
+  * If you work for a company that wants to allow you to contribute your work,
+    then you'll need to sign a [corporate CLA][].
+
+You generally only need to submit a CLA once, so if you've already submitted
+one (even if it was for a different project), you probably don't need to do it
+again.
+
+[individual CLA]: https://developers.google.com/open-source/cla/individual
+[corporate CLA]: https://developers.google.com/open-source/cla/corporate
+
+
+## Submitting a patch ##
+
+  1. It's generally best to start by opening a new issue describing the bug or
+     feature you're intending to fix.  Even if you think it's relatively minor,
+     it's helpful to know what people are working on.  Mention in the initial
+     issue that you are planning to work on that bug or feature so that it can
+     be assigned to you.
+
+  1. Follow the normal process of [forking][] the project, and setup a new
+     branch to work in.  It's important that each group of changes be done in
+     separate branches in order to ensure that a pull request only includes the
+     commits related to that bug or feature.
+
+  1. Go makes it very simple to ensure properly formatted code, so always run
+     `go fmt` on your code before committing it.  You should also run
+     [golint][] over your code.  As noted in the [golint readme][], it's not
+     strictly necessary that your code be completely "lint-free", but this will
+     help you find common style issues.
+
+  1. Any significant changes should almost always be accompanied by tests.  The
+     project already has good test coverage, so look at some of the existing
+     tests if you're unsure how to go about it.  [gocov][] and [gocov-html][]
+     are invaluable tools for seeing which parts of your code aren't being
+     exercised by your tests.
+
+  1. Do your best to have [well-formed commit messages][] for each change.
+     This provides consistency throughout the project, and ensures that commit
+     messages are able to be formatted properly by various git tools.
+
+  1. Finally, push the commits to your fork and submit a [pull request][].
+
+[forking]: https://help.github.com/articles/fork-a-repo
+[golint]: https://github.com/golang/lint
+[golint readme]: https://github.com/golang/lint/blob/master/README
+[gocov]: https://github.com/axw/gocov
+[gocov-html]: https://github.com/matm/gocov-html
+[well-formed commit messages]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
+[squash]: http://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits
+[pull request]: https://help.github.com/articles/creating-a-pull-request
diff --git a/vendor/github.com/google/gofuzz/LICENSE b/vendor/github.com/google/gofuzz/LICENSE
new file mode 100644
index 0000000..d645695
--- /dev/null
+++ b/vendor/github.com/google/gofuzz/LICENSE
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
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+
+      "You" (or "Your") shall mean an individual or Legal Entity
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+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
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+
+   7. Disclaimer of Warranty. Unless required by applicable law or
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+      Contributor provides its Contributions) on an "AS IS" BASIS,
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diff --git a/vendor/github.com/google/gofuzz/README.md b/vendor/github.com/google/gofuzz/README.md
new file mode 100644
index 0000000..64869af
--- /dev/null
+++ b/vendor/github.com/google/gofuzz/README.md
@@ -0,0 +1,71 @@
+gofuzz
+======
+
+gofuzz is a library for populating go objects with random values.
+
+[![GoDoc](https://godoc.org/github.com/google/gofuzz?status.png)](https://godoc.org/github.com/google/gofuzz)
+[![Travis](https://travis-ci.org/google/gofuzz.svg?branch=master)](https://travis-ci.org/google/gofuzz)
+
+This is useful for testing:
+
+* Do your project's objects really serialize/unserialize correctly in all cases?
+* Is there an incorrectly formatted object that will cause your project to panic?
+
+Import with ```import "github.com/google/gofuzz"```
+
+You can use it on single variables:
+```go
+f := fuzz.New()
+var myInt int
+f.Fuzz(&myInt) // myInt gets a random value.
+```
+
+You can use it on maps:
+```go
+f := fuzz.New().NilChance(0).NumElements(1, 1)
+var myMap map[ComplexKeyType]string
+f.Fuzz(&myMap) // myMap will have exactly one element.
+```
+
+Customize the chance of getting a nil pointer:
+```go
+f := fuzz.New().NilChance(.5)
+var fancyStruct struct {
+  A, B, C, D *string
+}
+f.Fuzz(&fancyStruct) // About half the pointers should be set.
+```
+
+You can even customize the randomization completely if needed:
+```go
+type MyEnum string
+const (
+        A MyEnum = "A"
+        B MyEnum = "B"
+)
+type MyInfo struct {
+        Type MyEnum
+        AInfo *string
+        BInfo *string
+}
+
+f := fuzz.New().NilChance(0).Funcs(
+        func(e *MyInfo, c fuzz.Continue) {
+                switch c.Intn(2) {
+                case 0:
+                        e.Type = A
+                        c.Fuzz(&e.AInfo)
+                case 1:
+                        e.Type = B
+                        c.Fuzz(&e.BInfo)
+                }
+        },
+)
+
+var myObject MyInfo
+f.Fuzz(&myObject) // Type will correspond to whether A or B info is set.
+```
+
+See more examples in ```example_test.go```.
+
+Happy testing!
diff --git a/vendor/github.com/google/gofuzz/doc.go b/vendor/github.com/google/gofuzz/doc.go
new file mode 100644
index 0000000..9f9956d
--- /dev/null
+++ b/vendor/github.com/google/gofuzz/doc.go
@@ -0,0 +1,18 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package fuzz is a library for populating go objects with random values.
+package fuzz
diff --git a/vendor/github.com/google/gofuzz/fuzz.go b/vendor/github.com/google/gofuzz/fuzz.go
new file mode 100644
index 0000000..1dfa80a
--- /dev/null
+++ b/vendor/github.com/google/gofuzz/fuzz.go
@@ -0,0 +1,487 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package fuzz
+
+import (
+	"fmt"
+	"math/rand"
+	"reflect"
+	"time"
+)
+
+// fuzzFuncMap is a map from a type to a fuzzFunc that handles that type.
+type fuzzFuncMap map[reflect.Type]reflect.Value
+
+// Fuzzer knows how to fill any object with random fields.
+type Fuzzer struct {
+	fuzzFuncs        fuzzFuncMap
+	defaultFuzzFuncs fuzzFuncMap
+	r                *rand.Rand
+	nilChance        float64
+	minElements      int
+	maxElements      int
+	maxDepth         int
+}
+
+// New returns a new Fuzzer. Customize your Fuzzer further by calling Funcs,
+// RandSource, NilChance, or NumElements in any order.
+func New() *Fuzzer {
+	return NewWithSeed(time.Now().UnixNano())
+}
+
+func NewWithSeed(seed int64) *Fuzzer {
+	f := &Fuzzer{
+		defaultFuzzFuncs: fuzzFuncMap{
+			reflect.TypeOf(&time.Time{}): reflect.ValueOf(fuzzTime),
+		},
+
+		fuzzFuncs:   fuzzFuncMap{},
+		r:           rand.New(rand.NewSource(seed)),
+		nilChance:   .2,
+		minElements: 1,
+		maxElements: 10,
+		maxDepth:    100,
+	}
+	return f
+}
+
+// Funcs adds each entry in fuzzFuncs as a custom fuzzing function.
+//
+// Each entry in fuzzFuncs must be a function taking two parameters.
+// The first parameter must be a pointer or map. It is the variable that
+// function will fill with random data. The second parameter must be a
+// fuzz.Continue, which will provide a source of randomness and a way
+// to automatically continue fuzzing smaller pieces of the first parameter.
+//
+// These functions are called sensibly, e.g., if you wanted custom string
+// fuzzing, the function `func(s *string, c fuzz.Continue)` would get
+// called and passed the address of strings. Maps and pointers will always
+// be made/new'd for you, ignoring the NilChange option. For slices, it
+// doesn't make much sense to  pre-create them--Fuzzer doesn't know how
+// long you want your slice--so take a pointer to a slice, and make it
+// yourself. (If you don't want your map/pointer type pre-made, take a
+// pointer to it, and make it yourself.) See the examples for a range of
+// custom functions.
+func (f *Fuzzer) Funcs(fuzzFuncs ...interface{}) *Fuzzer {
+	for i := range fuzzFuncs {
+		v := reflect.ValueOf(fuzzFuncs[i])
+		if v.Kind() != reflect.Func {
+			panic("Need only funcs!")
+		}
+		t := v.Type()
+		if t.NumIn() != 2 || t.NumOut() != 0 {
+			panic("Need 2 in and 0 out params!")
+		}
+		argT := t.In(0)
+		switch argT.Kind() {
+		case reflect.Ptr, reflect.Map:
+		default:
+			panic("fuzzFunc must take pointer or map type")
+		}
+		if t.In(1) != reflect.TypeOf(Continue{}) {
+			panic("fuzzFunc's second parameter must be type fuzz.Continue")
+		}
+		f.fuzzFuncs[argT] = v
+	}
+	return f
+}
+
+// RandSource causes f to get values from the given source of randomness.
+// Use if you want deterministic fuzzing.
+func (f *Fuzzer) RandSource(s rand.Source) *Fuzzer {
+	f.r = rand.New(s)
+	return f
+}
+
+// NilChance sets the probability of creating a nil pointer, map, or slice to
+// 'p'. 'p' should be between 0 (no nils) and 1 (all nils), inclusive.
+func (f *Fuzzer) NilChance(p float64) *Fuzzer {
+	if p < 0 || p > 1 {
+		panic("p should be between 0 and 1, inclusive.")
+	}
+	f.nilChance = p
+	return f
+}
+
+// NumElements sets the minimum and maximum number of elements that will be
+// added to a non-nil map or slice.
+func (f *Fuzzer) NumElements(atLeast, atMost int) *Fuzzer {
+	if atLeast > atMost {
+		panic("atLeast must be <= atMost")
+	}
+	if atLeast < 0 {
+		panic("atLeast must be >= 0")
+	}
+	f.minElements = atLeast
+	f.maxElements = atMost
+	return f
+}
+
+func (f *Fuzzer) genElementCount() int {
+	if f.minElements == f.maxElements {
+		return f.minElements
+	}
+	return f.minElements + f.r.Intn(f.maxElements-f.minElements+1)
+}
+
+func (f *Fuzzer) genShouldFill() bool {
+	return f.r.Float64() > f.nilChance
+}
+
+// MaxDepth sets the maximum number of recursive fuzz calls that will be made
+// before stopping.  This includes struct members, pointers, and map and slice
+// elements.
+func (f *Fuzzer) MaxDepth(d int) *Fuzzer {
+	f.maxDepth = d
+	return f
+}
+
+// Fuzz recursively fills all of obj's fields with something random.  First
+// this tries to find a custom fuzz function (see Funcs).  If there is no
+// custom function this tests whether the object implements fuzz.Interface and,
+// if so, calls Fuzz on it to fuzz itself.  If that fails, this will see if
+// there is a default fuzz function provided by this package.  If all of that
+// fails, this will generate random values for all primitive fields and then
+// recurse for all non-primitives.
+//
+// This is safe for cyclic or tree-like structs, up to a limit.  Use the
+// MaxDepth method to adjust how deep you need it to recurse.
+//
+// obj must be a pointer. Only exported (public) fields can be set (thanks,
+// golang :/ ) Intended for tests, so will panic on bad input or unimplemented
+// fields.
+func (f *Fuzzer) Fuzz(obj interface{}) {
+	v := reflect.ValueOf(obj)
+	if v.Kind() != reflect.Ptr {
+		panic("needed ptr!")
+	}
+	v = v.Elem()
+	f.fuzzWithContext(v, 0)
+}
+
+// FuzzNoCustom is just like Fuzz, except that any custom fuzz function for
+// obj's type will not be called and obj will not be tested for fuzz.Interface
+// conformance.  This applies only to obj and not other instances of obj's
+// type.
+// Not safe for cyclic or tree-like structs!
+// obj must be a pointer. Only exported (public) fields can be set (thanks, golang :/ )
+// Intended for tests, so will panic on bad input or unimplemented fields.
+func (f *Fuzzer) FuzzNoCustom(obj interface{}) {
+	v := reflect.ValueOf(obj)
+	if v.Kind() != reflect.Ptr {
+		panic("needed ptr!")
+	}
+	v = v.Elem()
+	f.fuzzWithContext(v, flagNoCustomFuzz)
+}
+
+const (
+	// Do not try to find a custom fuzz function.  Does not apply recursively.
+	flagNoCustomFuzz uint64 = 1 << iota
+)
+
+func (f *Fuzzer) fuzzWithContext(v reflect.Value, flags uint64) {
+	fc := &fuzzerContext{fuzzer: f}
+	fc.doFuzz(v, flags)
+}
+
+// fuzzerContext carries context about a single fuzzing run, which lets Fuzzer
+// be thread-safe.
+type fuzzerContext struct {
+	fuzzer   *Fuzzer
+	curDepth int
+}
+
+func (fc *fuzzerContext) doFuzz(v reflect.Value, flags uint64) {
+	if fc.curDepth >= fc.fuzzer.maxDepth {
+		return
+	}
+	fc.curDepth++
+	defer func() { fc.curDepth-- }()
+
+	if !v.CanSet() {
+		return
+	}
+
+	if flags&flagNoCustomFuzz == 0 {
+		// Check for both pointer and non-pointer custom functions.
+		if v.CanAddr() && fc.tryCustom(v.Addr()) {
+			return
+		}
+		if fc.tryCustom(v) {
+			return
+		}
+	}
+
+	if fn, ok := fillFuncMap[v.Kind()]; ok {
+		fn(v, fc.fuzzer.r)
+		return
+	}
+	switch v.Kind() {
+	case reflect.Map:
+		if fc.fuzzer.genShouldFill() {
+			v.Set(reflect.MakeMap(v.Type()))
+			n := fc.fuzzer.genElementCount()
+			for i := 0; i < n; i++ {
+				key := reflect.New(v.Type().Key()).Elem()
+				fc.doFuzz(key, 0)
+				val := reflect.New(v.Type().Elem()).Elem()
+				fc.doFuzz(val, 0)
+				v.SetMapIndex(key, val)
+			}
+			return
+		}
+		v.Set(reflect.Zero(v.Type()))
+	case reflect.Ptr:
+		if fc.fuzzer.genShouldFill() {
+			v.Set(reflect.New(v.Type().Elem()))
+			fc.doFuzz(v.Elem(), 0)
+			return
+		}
+		v.Set(reflect.Zero(v.Type()))
+	case reflect.Slice:
+		if fc.fuzzer.genShouldFill() {
+			n := fc.fuzzer.genElementCount()
+			v.Set(reflect.MakeSlice(v.Type(), n, n))
+			for i := 0; i < n; i++ {
+				fc.doFuzz(v.Index(i), 0)
+			}
+			return
+		}
+		v.Set(reflect.Zero(v.Type()))
+	case reflect.Array:
+		if fc.fuzzer.genShouldFill() {
+			n := v.Len()
+			for i := 0; i < n; i++ {
+				fc.doFuzz(v.Index(i), 0)
+			}
+			return
+		}
+		v.Set(reflect.Zero(v.Type()))
+	case reflect.Struct:
+		for i := 0; i < v.NumField(); i++ {
+			fc.doFuzz(v.Field(i), 0)
+		}
+	case reflect.Chan:
+		fallthrough
+	case reflect.Func:
+		fallthrough
+	case reflect.Interface:
+		fallthrough
+	default:
+		panic(fmt.Sprintf("Can't handle %#v", v.Interface()))
+	}
+}
+
+// tryCustom searches for custom handlers, and returns true iff it finds a match
+// and successfully randomizes v.
+func (fc *fuzzerContext) tryCustom(v reflect.Value) bool {
+	// First: see if we have a fuzz function for it.
+	doCustom, ok := fc.fuzzer.fuzzFuncs[v.Type()]
+	if !ok {
+		// Second: see if it can fuzz itself.
+		if v.CanInterface() {
+			intf := v.Interface()
+			if fuzzable, ok := intf.(Interface); ok {
+				fuzzable.Fuzz(Continue{fc: fc, Rand: fc.fuzzer.r})
+				return true
+			}
+		}
+		// Finally: see if there is a default fuzz function.
+		doCustom, ok = fc.fuzzer.defaultFuzzFuncs[v.Type()]
+		if !ok {
+			return false
+		}
+	}
+
+	switch v.Kind() {
+	case reflect.Ptr:
+		if v.IsNil() {
+			if !v.CanSet() {
+				return false
+			}
+			v.Set(reflect.New(v.Type().Elem()))
+		}
+	case reflect.Map:
+		if v.IsNil() {
+			if !v.CanSet() {
+				return false
+			}
+			v.Set(reflect.MakeMap(v.Type()))
+		}
+	default:
+		return false
+	}
+
+	doCustom.Call([]reflect.Value{v, reflect.ValueOf(Continue{
+		fc:   fc,
+		Rand: fc.fuzzer.r,
+	})})
+	return true
+}
+
+// Interface represents an object that knows how to fuzz itself.  Any time we
+// find a type that implements this interface we will delegate the act of
+// fuzzing itself.
+type Interface interface {
+	Fuzz(c Continue)
+}
+
+// Continue can be passed to custom fuzzing functions to allow them to use
+// the correct source of randomness and to continue fuzzing their members.
+type Continue struct {
+	fc *fuzzerContext
+
+	// For convenience, Continue implements rand.Rand via embedding.
+	// Use this for generating any randomness if you want your fuzzing
+	// to be repeatable for a given seed.
+	*rand.Rand
+}
+
+// Fuzz continues fuzzing obj. obj must be a pointer.
+func (c Continue) Fuzz(obj interface{}) {
+	v := reflect.ValueOf(obj)
+	if v.Kind() != reflect.Ptr {
+		panic("needed ptr!")
+	}
+	v = v.Elem()
+	c.fc.doFuzz(v, 0)
+}
+
+// FuzzNoCustom continues fuzzing obj, except that any custom fuzz function for
+// obj's type will not be called and obj will not be tested for fuzz.Interface
+// conformance.  This applies only to obj and not other instances of obj's
+// type.
+func (c Continue) FuzzNoCustom(obj interface{}) {
+	v := reflect.ValueOf(obj)
+	if v.Kind() != reflect.Ptr {
+		panic("needed ptr!")
+	}
+	v = v.Elem()
+	c.fc.doFuzz(v, flagNoCustomFuzz)
+}
+
+// RandString makes a random string up to 20 characters long. The returned string
+// may include a variety of (valid) UTF-8 encodings.
+func (c Continue) RandString() string {
+	return randString(c.Rand)
+}
+
+// RandUint64 makes random 64 bit numbers.
+// Weirdly, rand doesn't have a function that gives you 64 random bits.
+func (c Continue) RandUint64() uint64 {
+	return randUint64(c.Rand)
+}
+
+// RandBool returns true or false randomly.
+func (c Continue) RandBool() bool {
+	return randBool(c.Rand)
+}
+
+func fuzzInt(v reflect.Value, r *rand.Rand) {
+	v.SetInt(int64(randUint64(r)))
+}
+
+func fuzzUint(v reflect.Value, r *rand.Rand) {
+	v.SetUint(randUint64(r))
+}
+
+func fuzzTime(t *time.Time, c Continue) {
+	var sec, nsec int64
+	// Allow for about 1000 years of random time values, which keeps things
+	// like JSON parsing reasonably happy.
+	sec = c.Rand.Int63n(1000 * 365 * 24 * 60 * 60)
+	c.Fuzz(&nsec)
+	*t = time.Unix(sec, nsec)
+}
+
+var fillFuncMap = map[reflect.Kind]func(reflect.Value, *rand.Rand){
+	reflect.Bool: func(v reflect.Value, r *rand.Rand) {
+		v.SetBool(randBool(r))
+	},
+	reflect.Int:     fuzzInt,
+	reflect.Int8:    fuzzInt,
+	reflect.Int16:   fuzzInt,
+	reflect.Int32:   fuzzInt,
+	reflect.Int64:   fuzzInt,
+	reflect.Uint:    fuzzUint,
+	reflect.Uint8:   fuzzUint,
+	reflect.Uint16:  fuzzUint,
+	reflect.Uint32:  fuzzUint,
+	reflect.Uint64:  fuzzUint,
+	reflect.Uintptr: fuzzUint,
+	reflect.Float32: func(v reflect.Value, r *rand.Rand) {
+		v.SetFloat(float64(r.Float32()))
+	},
+	reflect.Float64: func(v reflect.Value, r *rand.Rand) {
+		v.SetFloat(r.Float64())
+	},
+	reflect.Complex64: func(v reflect.Value, r *rand.Rand) {
+		panic("unimplemented")
+	},
+	reflect.Complex128: func(v reflect.Value, r *rand.Rand) {
+		panic("unimplemented")
+	},
+	reflect.String: func(v reflect.Value, r *rand.Rand) {
+		v.SetString(randString(r))
+	},
+	reflect.UnsafePointer: func(v reflect.Value, r *rand.Rand) {
+		panic("unimplemented")
+	},
+}
+
+// randBool returns true or false randomly.
+func randBool(r *rand.Rand) bool {
+	if r.Int()&1 == 1 {
+		return true
+	}
+	return false
+}
+
+type charRange struct {
+	first, last rune
+}
+
+// choose returns a random unicode character from the given range, using the
+// given randomness source.
+func (r *charRange) choose(rand *rand.Rand) rune {
+	count := int64(r.last - r.first)
+	return r.first + rune(rand.Int63n(count))
+}
+
+var unicodeRanges = []charRange{
+	{' ', '~'},           // ASCII characters
+	{'\u00a0', '\u02af'}, // Multi-byte encoded characters
+	{'\u4e00', '\u9fff'}, // Common CJK (even longer encodings)
+}
+
+// randString makes a random string up to 20 characters long. The returned string
+// may include a variety of (valid) UTF-8 encodings.
+func randString(r *rand.Rand) string {
+	n := r.Intn(20)
+	runes := make([]rune, n)
+	for i := range runes {
+		runes[i] = unicodeRanges[r.Intn(len(unicodeRanges))].choose(r)
+	}
+	return string(runes)
+}
+
+// randUint64 makes random 64 bit numbers.
+// Weirdly, rand doesn't have a function that gives you 64 random bits.
+func randUint64(r *rand.Rand) uint64 {
+	return uint64(r.Uint32())<<32 | uint64(r.Uint32())
+}
diff --git a/vendor/github.com/google/uuid/.travis.yml b/vendor/github.com/google/uuid/.travis.yml
new file mode 100644
index 0000000..d8156a6
--- /dev/null
+++ b/vendor/github.com/google/uuid/.travis.yml
@@ -0,0 +1,9 @@
+language: go
+
+go:
+  - 1.4.3
+  - 1.5.3
+  - tip
+
+script:
+  - go test -v ./...
diff --git a/vendor/github.com/google/uuid/CONTRIBUTING.md b/vendor/github.com/google/uuid/CONTRIBUTING.md
new file mode 100644
index 0000000..04fdf09
--- /dev/null
+++ b/vendor/github.com/google/uuid/CONTRIBUTING.md
@@ -0,0 +1,10 @@
+# How to contribute
+
+We definitely welcome patches and contribution to this project!
+
+### Legal requirements
+
+In order to protect both you and ourselves, you will need to sign the
+[Contributor License Agreement](https://cla.developers.google.com/clas).
+
+You may have already signed it for other Google projects.
diff --git a/vendor/github.com/google/uuid/CONTRIBUTORS b/vendor/github.com/google/uuid/CONTRIBUTORS
new file mode 100644
index 0000000..b4bb97f
--- /dev/null
+++ b/vendor/github.com/google/uuid/CONTRIBUTORS
@@ -0,0 +1,9 @@
+Paul Borman <borman@google.com>
+bmatsuo
+shawnps
+theory
+jboverfelt
+dsymonds
+cd1
+wallclockbuilder
+dansouza
diff --git a/vendor/github.com/google/uuid/LICENSE b/vendor/github.com/google/uuid/LICENSE
new file mode 100644
index 0000000..5dc6826
--- /dev/null
+++ b/vendor/github.com/google/uuid/LICENSE
@@ -0,0 +1,27 @@
+Copyright (c) 2009,2014 Google Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/github.com/google/uuid/README.md b/vendor/github.com/google/uuid/README.md
new file mode 100644
index 0000000..9d92c11
--- /dev/null
+++ b/vendor/github.com/google/uuid/README.md
@@ -0,0 +1,19 @@
+# uuid ![build status](https://travis-ci.org/google/uuid.svg?branch=master)
+The uuid package generates and inspects UUIDs based on
+[RFC 4122](http://tools.ietf.org/html/rfc4122)
+and DCE 1.1: Authentication and Security Services. 
+
+This package is based on the github.com/pborman/uuid package (previously named
+code.google.com/p/go-uuid).  It differs from these earlier packages in that
+a UUID is a 16 byte array rather than a byte slice.  One loss due to this
+change is the ability to represent an invalid UUID (vs a NIL UUID).
+
+###### Install
+`go get github.com/google/uuid`
+
+###### Documentation 
+[![GoDoc](https://godoc.org/github.com/google/uuid?status.svg)](http://godoc.org/github.com/google/uuid)
+
+Full `go doc` style documentation for the package can be viewed online without
+installing this package by using the GoDoc site here: 
+http://godoc.org/github.com/google/uuid
diff --git a/vendor/github.com/google/uuid/dce.go b/vendor/github.com/google/uuid/dce.go
new file mode 100644
index 0000000..fa820b9
--- /dev/null
+++ b/vendor/github.com/google/uuid/dce.go
@@ -0,0 +1,80 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"encoding/binary"
+	"fmt"
+	"os"
+)
+
+// A Domain represents a Version 2 domain
+type Domain byte
+
+// Domain constants for DCE Security (Version 2) UUIDs.
+const (
+	Person = Domain(0)
+	Group  = Domain(1)
+	Org    = Domain(2)
+)
+
+// NewDCESecurity returns a DCE Security (Version 2) UUID.
+//
+// The domain should be one of Person, Group or Org.
+// On a POSIX system the id should be the users UID for the Person
+// domain and the users GID for the Group.  The meaning of id for
+// the domain Org or on non-POSIX systems is site defined.
+//
+// For a given domain/id pair the same token may be returned for up to
+// 7 minutes and 10 seconds.
+func NewDCESecurity(domain Domain, id uint32) (UUID, error) {
+	uuid, err := NewUUID()
+	if err == nil {
+		uuid[6] = (uuid[6] & 0x0f) | 0x20 // Version 2
+		uuid[9] = byte(domain)
+		binary.BigEndian.PutUint32(uuid[0:], id)
+	}
+	return uuid, err
+}
+
+// NewDCEPerson returns a DCE Security (Version 2) UUID in the person
+// domain with the id returned by os.Getuid.
+//
+//  NewDCESecurity(Person, uint32(os.Getuid()))
+func NewDCEPerson() (UUID, error) {
+	return NewDCESecurity(Person, uint32(os.Getuid()))
+}
+
+// NewDCEGroup returns a DCE Security (Version 2) UUID in the group
+// domain with the id returned by os.Getgid.
+//
+//  NewDCESecurity(Group, uint32(os.Getgid()))
+func NewDCEGroup() (UUID, error) {
+	return NewDCESecurity(Group, uint32(os.Getgid()))
+}
+
+// Domain returns the domain for a Version 2 UUID.  Domains are only defined
+// for Version 2 UUIDs.
+func (uuid UUID) Domain() Domain {
+	return Domain(uuid[9])
+}
+
+// ID returns the id for a Version 2 UUID. IDs are only defined for Version 2
+// UUIDs.
+func (uuid UUID) ID() uint32 {
+	return binary.BigEndian.Uint32(uuid[0:4])
+}
+
+func (d Domain) String() string {
+	switch d {
+	case Person:
+		return "Person"
+	case Group:
+		return "Group"
+	case Org:
+		return "Org"
+	}
+	return fmt.Sprintf("Domain%d", int(d))
+}
diff --git a/vendor/github.com/google/uuid/doc.go b/vendor/github.com/google/uuid/doc.go
new file mode 100644
index 0000000..5b8a4b9
--- /dev/null
+++ b/vendor/github.com/google/uuid/doc.go
@@ -0,0 +1,12 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package uuid generates and inspects UUIDs.
+//
+// UUIDs are based on RFC 4122 and DCE 1.1: Authentication and Security
+// Services.
+//
+// A UUID is a 16 byte (128 bit) array.  UUIDs may be used as keys to
+// maps or compared directly.
+package uuid
diff --git a/vendor/github.com/google/uuid/go.mod b/vendor/github.com/google/uuid/go.mod
new file mode 100644
index 0000000..fc84cd7
--- /dev/null
+++ b/vendor/github.com/google/uuid/go.mod
@@ -0,0 +1 @@
+module github.com/google/uuid
diff --git a/vendor/github.com/google/uuid/hash.go b/vendor/github.com/google/uuid/hash.go
new file mode 100644
index 0000000..b174616
--- /dev/null
+++ b/vendor/github.com/google/uuid/hash.go
@@ -0,0 +1,53 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"crypto/md5"
+	"crypto/sha1"
+	"hash"
+)
+
+// Well known namespace IDs and UUIDs
+var (
+	NameSpaceDNS  = Must(Parse("6ba7b810-9dad-11d1-80b4-00c04fd430c8"))
+	NameSpaceURL  = Must(Parse("6ba7b811-9dad-11d1-80b4-00c04fd430c8"))
+	NameSpaceOID  = Must(Parse("6ba7b812-9dad-11d1-80b4-00c04fd430c8"))
+	NameSpaceX500 = Must(Parse("6ba7b814-9dad-11d1-80b4-00c04fd430c8"))
+	Nil           UUID // empty UUID, all zeros
+)
+
+// NewHash returns a new UUID derived from the hash of space concatenated with
+// data generated by h.  The hash should be at least 16 byte in length.  The
+// first 16 bytes of the hash are used to form the UUID.  The version of the
+// UUID will be the lower 4 bits of version.  NewHash is used to implement
+// NewMD5 and NewSHA1.
+func NewHash(h hash.Hash, space UUID, data []byte, version int) UUID {
+	h.Reset()
+	h.Write(space[:])
+	h.Write(data)
+	s := h.Sum(nil)
+	var uuid UUID
+	copy(uuid[:], s)
+	uuid[6] = (uuid[6] & 0x0f) | uint8((version&0xf)<<4)
+	uuid[8] = (uuid[8] & 0x3f) | 0x80 // RFC 4122 variant
+	return uuid
+}
+
+// NewMD5 returns a new MD5 (Version 3) UUID based on the
+// supplied name space and data.  It is the same as calling:
+//
+//  NewHash(md5.New(), space, data, 3)
+func NewMD5(space UUID, data []byte) UUID {
+	return NewHash(md5.New(), space, data, 3)
+}
+
+// NewSHA1 returns a new SHA1 (Version 5) UUID based on the
+// supplied name space and data.  It is the same as calling:
+//
+//  NewHash(sha1.New(), space, data, 5)
+func NewSHA1(space UUID, data []byte) UUID {
+	return NewHash(sha1.New(), space, data, 5)
+}
diff --git a/vendor/github.com/google/uuid/marshal.go b/vendor/github.com/google/uuid/marshal.go
new file mode 100644
index 0000000..7f9e0c6
--- /dev/null
+++ b/vendor/github.com/google/uuid/marshal.go
@@ -0,0 +1,37 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import "fmt"
+
+// MarshalText implements encoding.TextMarshaler.
+func (uuid UUID) MarshalText() ([]byte, error) {
+	var js [36]byte
+	encodeHex(js[:], uuid)
+	return js[:], nil
+}
+
+// UnmarshalText implements encoding.TextUnmarshaler.
+func (uuid *UUID) UnmarshalText(data []byte) error {
+	id, err := ParseBytes(data)
+	if err == nil {
+		*uuid = id
+	}
+	return err
+}
+
+// MarshalBinary implements encoding.BinaryMarshaler.
+func (uuid UUID) MarshalBinary() ([]byte, error) {
+	return uuid[:], nil
+}
+
+// UnmarshalBinary implements encoding.BinaryUnmarshaler.
+func (uuid *UUID) UnmarshalBinary(data []byte) error {
+	if len(data) != 16 {
+		return fmt.Errorf("invalid UUID (got %d bytes)", len(data))
+	}
+	copy(uuid[:], data)
+	return nil
+}
diff --git a/vendor/github.com/google/uuid/node.go b/vendor/github.com/google/uuid/node.go
new file mode 100644
index 0000000..d651a2b
--- /dev/null
+++ b/vendor/github.com/google/uuid/node.go
@@ -0,0 +1,90 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"sync"
+)
+
+var (
+	nodeMu sync.Mutex
+	ifname string  // name of interface being used
+	nodeID [6]byte // hardware for version 1 UUIDs
+	zeroID [6]byte // nodeID with only 0's
+)
+
+// NodeInterface returns the name of the interface from which the NodeID was
+// derived.  The interface "user" is returned if the NodeID was set by
+// SetNodeID.
+func NodeInterface() string {
+	defer nodeMu.Unlock()
+	nodeMu.Lock()
+	return ifname
+}
+
+// SetNodeInterface selects the hardware address to be used for Version 1 UUIDs.
+// If name is "" then the first usable interface found will be used or a random
+// Node ID will be generated.  If a named interface cannot be found then false
+// is returned.
+//
+// SetNodeInterface never fails when name is "".
+func SetNodeInterface(name string) bool {
+	defer nodeMu.Unlock()
+	nodeMu.Lock()
+	return setNodeInterface(name)
+}
+
+func setNodeInterface(name string) bool {
+	iname, addr := getHardwareInterface(name) // null implementation for js
+	if iname != "" && addr != nil {
+		ifname = iname
+		copy(nodeID[:], addr)
+		return true
+	}
+
+	// We found no interfaces with a valid hardware address.  If name
+	// does not specify a specific interface generate a random Node ID
+	// (section 4.1.6)
+	if name == "" {
+		ifname = "random"
+		randomBits(nodeID[:])
+		return true
+	}
+	return false
+}
+
+// NodeID returns a slice of a copy of the current Node ID, setting the Node ID
+// if not already set.
+func NodeID() []byte {
+	defer nodeMu.Unlock()
+	nodeMu.Lock()
+	if nodeID == zeroID {
+		setNodeInterface("")
+	}
+	nid := nodeID
+	return nid[:]
+}
+
+// SetNodeID sets the Node ID to be used for Version 1 UUIDs.  The first 6 bytes
+// of id are used.  If id is less than 6 bytes then false is returned and the
+// Node ID is not set.
+func SetNodeID(id []byte) bool {
+	if len(id) < 6 {
+		return false
+	}
+	defer nodeMu.Unlock()
+	nodeMu.Lock()
+	copy(nodeID[:], id)
+	ifname = "user"
+	return true
+}
+
+// NodeID returns the 6 byte node id encoded in uuid.  It returns nil if uuid is
+// not valid.  The NodeID is only well defined for version 1 and 2 UUIDs.
+func (uuid UUID) NodeID() []byte {
+	var node [6]byte
+	copy(node[:], uuid[10:])
+	return node[:]
+}
diff --git a/vendor/github.com/google/uuid/node_js.go b/vendor/github.com/google/uuid/node_js.go
new file mode 100644
index 0000000..24b78ed
--- /dev/null
+++ b/vendor/github.com/google/uuid/node_js.go
@@ -0,0 +1,12 @@
+// Copyright 2017 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build js
+
+package uuid
+
+// getHardwareInterface returns nil values for the JS version of the code.
+// This remvoves the "net" dependency, because it is not used in the browser.
+// Using the "net" library inflates the size of the transpiled JS code by 673k bytes.
+func getHardwareInterface(name string) (string, []byte) { return "", nil }
diff --git a/vendor/github.com/google/uuid/node_net.go b/vendor/github.com/google/uuid/node_net.go
new file mode 100644
index 0000000..0cbbcdd
--- /dev/null
+++ b/vendor/github.com/google/uuid/node_net.go
@@ -0,0 +1,33 @@
+// Copyright 2017 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !js
+
+package uuid
+
+import "net"
+
+var interfaces []net.Interface // cached list of interfaces
+
+// getHardwareInterface returns the name and hardware address of interface name.
+// If name is "" then the name and hardware address of one of the system's
+// interfaces is returned.  If no interfaces are found (name does not exist or
+// there are no interfaces) then "", nil is returned.
+//
+// Only addresses of at least 6 bytes are returned.
+func getHardwareInterface(name string) (string, []byte) {
+	if interfaces == nil {
+		var err error
+		interfaces, err = net.Interfaces()
+		if err != nil {
+			return "", nil
+		}
+	}
+	for _, ifs := range interfaces {
+		if len(ifs.HardwareAddr) >= 6 && (name == "" || name == ifs.Name) {
+			return ifs.Name, ifs.HardwareAddr
+		}
+	}
+	return "", nil
+}
diff --git a/vendor/github.com/google/uuid/sql.go b/vendor/github.com/google/uuid/sql.go
new file mode 100644
index 0000000..f326b54
--- /dev/null
+++ b/vendor/github.com/google/uuid/sql.go
@@ -0,0 +1,59 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"database/sql/driver"
+	"fmt"
+)
+
+// Scan implements sql.Scanner so UUIDs can be read from databases transparently
+// Currently, database types that map to string and []byte are supported. Please
+// consult database-specific driver documentation for matching types.
+func (uuid *UUID) Scan(src interface{}) error {
+	switch src := src.(type) {
+	case nil:
+		return nil
+
+	case string:
+		// if an empty UUID comes from a table, we return a null UUID
+		if src == "" {
+			return nil
+		}
+
+		// see Parse for required string format
+		u, err := Parse(src)
+		if err != nil {
+			return fmt.Errorf("Scan: %v", err)
+		}
+
+		*uuid = u
+
+	case []byte:
+		// if an empty UUID comes from a table, we return a null UUID
+		if len(src) == 0 {
+			return nil
+		}
+
+		// assumes a simple slice of bytes if 16 bytes
+		// otherwise attempts to parse
+		if len(src) != 16 {
+			return uuid.Scan(string(src))
+		}
+		copy((*uuid)[:], src)
+
+	default:
+		return fmt.Errorf("Scan: unable to scan type %T into UUID", src)
+	}
+
+	return nil
+}
+
+// Value implements sql.Valuer so that UUIDs can be written to databases
+// transparently. Currently, UUIDs map to strings. Please consult
+// database-specific driver documentation for matching types.
+func (uuid UUID) Value() (driver.Value, error) {
+	return uuid.String(), nil
+}
diff --git a/vendor/github.com/google/uuid/time.go b/vendor/github.com/google/uuid/time.go
new file mode 100644
index 0000000..e6ef06c
--- /dev/null
+++ b/vendor/github.com/google/uuid/time.go
@@ -0,0 +1,123 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"encoding/binary"
+	"sync"
+	"time"
+)
+
+// A Time represents a time as the number of 100's of nanoseconds since 15 Oct
+// 1582.
+type Time int64
+
+const (
+	lillian    = 2299160          // Julian day of 15 Oct 1582
+	unix       = 2440587          // Julian day of 1 Jan 1970
+	epoch      = unix - lillian   // Days between epochs
+	g1582      = epoch * 86400    // seconds between epochs
+	g1582ns100 = g1582 * 10000000 // 100s of a nanoseconds between epochs
+)
+
+var (
+	timeMu   sync.Mutex
+	lasttime uint64 // last time we returned
+	clockSeq uint16 // clock sequence for this run
+
+	timeNow = time.Now // for testing
+)
+
+// UnixTime converts t the number of seconds and nanoseconds using the Unix
+// epoch of 1 Jan 1970.
+func (t Time) UnixTime() (sec, nsec int64) {
+	sec = int64(t - g1582ns100)
+	nsec = (sec % 10000000) * 100
+	sec /= 10000000
+	return sec, nsec
+}
+
+// GetTime returns the current Time (100s of nanoseconds since 15 Oct 1582) and
+// clock sequence as well as adjusting the clock sequence as needed.  An error
+// is returned if the current time cannot be determined.
+func GetTime() (Time, uint16, error) {
+	defer timeMu.Unlock()
+	timeMu.Lock()
+	return getTime()
+}
+
+func getTime() (Time, uint16, error) {
+	t := timeNow()
+
+	// If we don't have a clock sequence already, set one.
+	if clockSeq == 0 {
+		setClockSequence(-1)
+	}
+	now := uint64(t.UnixNano()/100) + g1582ns100
+
+	// If time has gone backwards with this clock sequence then we
+	// increment the clock sequence
+	if now <= lasttime {
+		clockSeq = ((clockSeq + 1) & 0x3fff) | 0x8000
+	}
+	lasttime = now
+	return Time(now), clockSeq, nil
+}
+
+// ClockSequence returns the current clock sequence, generating one if not
+// already set.  The clock sequence is only used for Version 1 UUIDs.
+//
+// The uuid package does not use global static storage for the clock sequence or
+// the last time a UUID was generated.  Unless SetClockSequence is used, a new
+// random clock sequence is generated the first time a clock sequence is
+// requested by ClockSequence, GetTime, or NewUUID.  (section 4.2.1.1)
+func ClockSequence() int {
+	defer timeMu.Unlock()
+	timeMu.Lock()
+	return clockSequence()
+}
+
+func clockSequence() int {
+	if clockSeq == 0 {
+		setClockSequence(-1)
+	}
+	return int(clockSeq & 0x3fff)
+}
+
+// SetClockSequence sets the clock sequence to the lower 14 bits of seq.  Setting to
+// -1 causes a new sequence to be generated.
+func SetClockSequence(seq int) {
+	defer timeMu.Unlock()
+	timeMu.Lock()
+	setClockSequence(seq)
+}
+
+func setClockSequence(seq int) {
+	if seq == -1 {
+		var b [2]byte
+		randomBits(b[:]) // clock sequence
+		seq = int(b[0])<<8 | int(b[1])
+	}
+	oldSeq := clockSeq
+	clockSeq = uint16(seq&0x3fff) | 0x8000 // Set our variant
+	if oldSeq != clockSeq {
+		lasttime = 0
+	}
+}
+
+// Time returns the time in 100s of nanoseconds since 15 Oct 1582 encoded in
+// uuid.  The time is only defined for version 1 and 2 UUIDs.
+func (uuid UUID) Time() Time {
+	time := int64(binary.BigEndian.Uint32(uuid[0:4]))
+	time |= int64(binary.BigEndian.Uint16(uuid[4:6])) << 32
+	time |= int64(binary.BigEndian.Uint16(uuid[6:8])&0xfff) << 48
+	return Time(time)
+}
+
+// ClockSequence returns the clock sequence encoded in uuid.
+// The clock sequence is only well defined for version 1 and 2 UUIDs.
+func (uuid UUID) ClockSequence() int {
+	return int(binary.BigEndian.Uint16(uuid[8:10])) & 0x3fff
+}
diff --git a/vendor/github.com/google/uuid/util.go b/vendor/github.com/google/uuid/util.go
new file mode 100644
index 0000000..5ea6c73
--- /dev/null
+++ b/vendor/github.com/google/uuid/util.go
@@ -0,0 +1,43 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"io"
+)
+
+// randomBits completely fills slice b with random data.
+func randomBits(b []byte) {
+	if _, err := io.ReadFull(rander, b); err != nil {
+		panic(err.Error()) // rand should never fail
+	}
+}
+
+// xvalues returns the value of a byte as a hexadecimal digit or 255.
+var xvalues = [256]byte{
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 255, 255, 255, 255, 255, 255,
+	255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+}
+
+// xtob converts hex characters x1 and x2 into a byte.
+func xtob(x1, x2 byte) (byte, bool) {
+	b1 := xvalues[x1]
+	b2 := xvalues[x2]
+	return (b1 << 4) | b2, b1 != 255 && b2 != 255
+}
diff --git a/vendor/github.com/google/uuid/uuid.go b/vendor/github.com/google/uuid/uuid.go
new file mode 100644
index 0000000..524404c
--- /dev/null
+++ b/vendor/github.com/google/uuid/uuid.go
@@ -0,0 +1,245 @@
+// Copyright 2018 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// A UUID is a 128 bit (16 byte) Universal Unique IDentifier as defined in RFC
+// 4122.
+type UUID [16]byte
+
+// A Version represents a UUID's version.
+type Version byte
+
+// A Variant represents a UUID's variant.
+type Variant byte
+
+// Constants returned by Variant.
+const (
+	Invalid   = Variant(iota) // Invalid UUID
+	RFC4122                   // The variant specified in RFC4122
+	Reserved                  // Reserved, NCS backward compatibility.
+	Microsoft                 // Reserved, Microsoft Corporation backward compatibility.
+	Future                    // Reserved for future definition.
+)
+
+var rander = rand.Reader // random function
+
+// Parse decodes s into a UUID or returns an error.  Both the standard UUID
+// forms of xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx and
+// urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx are decoded as well as the
+// Microsoft encoding {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} and the raw hex
+// encoding: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.
+func Parse(s string) (UUID, error) {
+	var uuid UUID
+	switch len(s) {
+	// xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+	case 36:
+
+	// urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+	case 36 + 9:
+		if strings.ToLower(s[:9]) != "urn:uuid:" {
+			return uuid, fmt.Errorf("invalid urn prefix: %q", s[:9])
+		}
+		s = s[9:]
+
+	// {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
+	case 36 + 2:
+		s = s[1:]
+
+	// xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+	case 32:
+		var ok bool
+		for i := range uuid {
+			uuid[i], ok = xtob(s[i*2], s[i*2+1])
+			if !ok {
+				return uuid, errors.New("invalid UUID format")
+			}
+		}
+		return uuid, nil
+	default:
+		return uuid, fmt.Errorf("invalid UUID length: %d", len(s))
+	}
+	// s is now at least 36 bytes long
+	// it must be of the form  xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+	if s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-' {
+		return uuid, errors.New("invalid UUID format")
+	}
+	for i, x := range [16]int{
+		0, 2, 4, 6,
+		9, 11,
+		14, 16,
+		19, 21,
+		24, 26, 28, 30, 32, 34} {
+		v, ok := xtob(s[x], s[x+1])
+		if !ok {
+			return uuid, errors.New("invalid UUID format")
+		}
+		uuid[i] = v
+	}
+	return uuid, nil
+}
+
+// ParseBytes is like Parse, except it parses a byte slice instead of a string.
+func ParseBytes(b []byte) (UUID, error) {
+	var uuid UUID
+	switch len(b) {
+	case 36: // xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+	case 36 + 9: // urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+		if !bytes.Equal(bytes.ToLower(b[:9]), []byte("urn:uuid:")) {
+			return uuid, fmt.Errorf("invalid urn prefix: %q", b[:9])
+		}
+		b = b[9:]
+	case 36 + 2: // {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
+		b = b[1:]
+	case 32: // xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+		var ok bool
+		for i := 0; i < 32; i += 2 {
+			uuid[i/2], ok = xtob(b[i], b[i+1])
+			if !ok {
+				return uuid, errors.New("invalid UUID format")
+			}
+		}
+		return uuid, nil
+	default:
+		return uuid, fmt.Errorf("invalid UUID length: %d", len(b))
+	}
+	// s is now at least 36 bytes long
+	// it must be of the form  xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+	if b[8] != '-' || b[13] != '-' || b[18] != '-' || b[23] != '-' {
+		return uuid, errors.New("invalid UUID format")
+	}
+	for i, x := range [16]int{
+		0, 2, 4, 6,
+		9, 11,
+		14, 16,
+		19, 21,
+		24, 26, 28, 30, 32, 34} {
+		v, ok := xtob(b[x], b[x+1])
+		if !ok {
+			return uuid, errors.New("invalid UUID format")
+		}
+		uuid[i] = v
+	}
+	return uuid, nil
+}
+
+// MustParse is like Parse but panics if the string cannot be parsed.
+// It simplifies safe initialization of global variables holding compiled UUIDs.
+func MustParse(s string) UUID {
+	uuid, err := Parse(s)
+	if err != nil {
+		panic(`uuid: Parse(` + s + `): ` + err.Error())
+	}
+	return uuid
+}
+
+// FromBytes creates a new UUID from a byte slice. Returns an error if the slice
+// does not have a length of 16. The bytes are copied from the slice.
+func FromBytes(b []byte) (uuid UUID, err error) {
+	err = uuid.UnmarshalBinary(b)
+	return uuid, err
+}
+
+// Must returns uuid if err is nil and panics otherwise.
+func Must(uuid UUID, err error) UUID {
+	if err != nil {
+		panic(err)
+	}
+	return uuid
+}
+
+// String returns the string form of uuid, xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+// , or "" if uuid is invalid.
+func (uuid UUID) String() string {
+	var buf [36]byte
+	encodeHex(buf[:], uuid)
+	return string(buf[:])
+}
+
+// URN returns the RFC 2141 URN form of uuid,
+// urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx,  or "" if uuid is invalid.
+func (uuid UUID) URN() string {
+	var buf [36 + 9]byte
+	copy(buf[:], "urn:uuid:")
+	encodeHex(buf[9:], uuid)
+	return string(buf[:])
+}
+
+func encodeHex(dst []byte, uuid UUID) {
+	hex.Encode(dst, uuid[:4])
+	dst[8] = '-'
+	hex.Encode(dst[9:13], uuid[4:6])
+	dst[13] = '-'
+	hex.Encode(dst[14:18], uuid[6:8])
+	dst[18] = '-'
+	hex.Encode(dst[19:23], uuid[8:10])
+	dst[23] = '-'
+	hex.Encode(dst[24:], uuid[10:])
+}
+
+// Variant returns the variant encoded in uuid.
+func (uuid UUID) Variant() Variant {
+	switch {
+	case (uuid[8] & 0xc0) == 0x80:
+		return RFC4122
+	case (uuid[8] & 0xe0) == 0xc0:
+		return Microsoft
+	case (uuid[8] & 0xe0) == 0xe0:
+		return Future
+	default:
+		return Reserved
+	}
+}
+
+// Version returns the version of uuid.
+func (uuid UUID) Version() Version {
+	return Version(uuid[6] >> 4)
+}
+
+func (v Version) String() string {
+	if v > 15 {
+		return fmt.Sprintf("BAD_VERSION_%d", v)
+	}
+	return fmt.Sprintf("VERSION_%d", v)
+}
+
+func (v Variant) String() string {
+	switch v {
+	case RFC4122:
+		return "RFC4122"
+	case Reserved:
+		return "Reserved"
+	case Microsoft:
+		return "Microsoft"
+	case Future:
+		return "Future"
+	case Invalid:
+		return "Invalid"
+	}
+	return fmt.Sprintf("BadVariant%d", int(v))
+}
+
+// SetRand sets the random number generator to r, which implements io.Reader.
+// If r.Read returns an error when the package requests random data then
+// a panic will be issued.
+//
+// Calling SetRand with nil sets the random number generator to the default
+// generator.
+func SetRand(r io.Reader) {
+	if r == nil {
+		rander = rand.Reader
+		return
+	}
+	rander = r
+}
diff --git a/vendor/github.com/google/uuid/version1.go b/vendor/github.com/google/uuid/version1.go
new file mode 100644
index 0000000..199a1ac
--- /dev/null
+++ b/vendor/github.com/google/uuid/version1.go
@@ -0,0 +1,44 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"encoding/binary"
+)
+
+// NewUUID returns a Version 1 UUID based on the current NodeID and clock
+// sequence, and the current time.  If the NodeID has not been set by SetNodeID
+// or SetNodeInterface then it will be set automatically.  If the NodeID cannot
+// be set NewUUID returns nil.  If clock sequence has not been set by
+// SetClockSequence then it will be set automatically.  If GetTime fails to
+// return the current NewUUID returns nil and an error.
+//
+// In most cases, New should be used.
+func NewUUID() (UUID, error) {
+	nodeMu.Lock()
+	if nodeID == zeroID {
+		setNodeInterface("")
+	}
+	nodeMu.Unlock()
+
+	var uuid UUID
+	now, seq, err := GetTime()
+	if err != nil {
+		return uuid, err
+	}
+
+	timeLow := uint32(now & 0xffffffff)
+	timeMid := uint16((now >> 32) & 0xffff)
+	timeHi := uint16((now >> 48) & 0x0fff)
+	timeHi |= 0x1000 // Version 1
+
+	binary.BigEndian.PutUint32(uuid[0:], timeLow)
+	binary.BigEndian.PutUint16(uuid[4:], timeMid)
+	binary.BigEndian.PutUint16(uuid[6:], timeHi)
+	binary.BigEndian.PutUint16(uuid[8:], seq)
+	copy(uuid[10:], nodeID[:])
+
+	return uuid, nil
+}
diff --git a/vendor/github.com/google/uuid/version4.go b/vendor/github.com/google/uuid/version4.go
new file mode 100644
index 0000000..84af91c
--- /dev/null
+++ b/vendor/github.com/google/uuid/version4.go
@@ -0,0 +1,38 @@
+// Copyright 2016 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import "io"
+
+// New creates a new random UUID or panics.  New is equivalent to
+// the expression
+//
+//    uuid.Must(uuid.NewRandom())
+func New() UUID {
+	return Must(NewRandom())
+}
+
+// NewRandom returns a Random (Version 4) UUID.
+//
+// The strength of the UUIDs is based on the strength of the crypto/rand
+// package.
+//
+// A note about uniqueness derived from the UUID Wikipedia entry:
+//
+//  Randomly generated UUIDs have 122 random bits.  One's annual risk of being
+//  hit by a meteorite is estimated to be one chance in 17 billion, that
+//  means the probability is about 0.00000000006 (6 × 10−11),
+//  equivalent to the odds of creating a few tens of trillions of UUIDs in a
+//  year and having one duplicate.
+func NewRandom() (UUID, error) {
+	var uuid UUID
+	_, err := io.ReadFull(rander, uuid[:])
+	if err != nil {
+		return Nil, err
+	}
+	uuid[6] = (uuid[6] & 0x0f) | 0x40 // Version 4
+	uuid[8] = (uuid[8] & 0x3f) | 0x80 // Variant is 10
+	return uuid, nil
+}