diff --git a/vendor/github.com/deckarep/golang-set/set.go b/vendor/github.com/deckarep/golang-set/set.go
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+/*
+Open Source Initiative OSI - The MIT License (MIT):Licensing
+
+The MIT License (MIT)
+Copyright (c) 2013 Ralph Caraveo (deckarep@gmail.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+// Package mapset implements a simple and generic set collection.
+// Items stored within it are unordered and unique. It supports
+// typical set operations: membership testing, intersection, union,
+// difference, symmetric difference and cloning.
+//
+// Package mapset provides two implementations of the Set
+// interface. The default implementation is safe for concurrent
+// access, but a non-thread-safe implementation is also provided for
+// programs that can benefit from the slight speed improvement and
+// that can enforce mutual exclusion through other means.
+package mapset
+
+// Set is the primary interface provided by the mapset package.  It
+// represents an unordered set of data and a large number of
+// operations that can be applied to that set.
+type Set interface {
+	// Adds an element to the set. Returns whether
+	// the item was added.
+	Add(i interface{}) bool
+
+	// Returns the number of elements in the set.
+	Cardinality() int
+
+	// Removes all elements from the set, leaving
+	// the empty set.
+	Clear()
+
+	// Returns a clone of the set using the same
+	// implementation, duplicating all keys.
+	Clone() Set
+
+	// Returns whether the given items
+	// are all in the set.
+	Contains(i ...interface{}) bool
+
+	// Returns the difference between this set
+	// and other. The returned set will contain
+	// all elements of this set that are not also
+	// elements of other.
+	//
+	// Note that the argument to Difference
+	// must be of the same type as the receiver
+	// of the method. Otherwise, Difference will
+	// panic.
+	Difference(other Set) Set
+
+	// Determines if two sets are equal to each
+	// other. If they have the same cardinality
+	// and contain the same elements, they are
+	// considered equal. The order in which
+	// the elements were added is irrelevant.
+	//
+	// Note that the argument to Equal must be
+	// of the same type as the receiver of the
+	// method. Otherwise, Equal will panic.
+	Equal(other Set) bool
+
+	// Returns a new set containing only the elements
+	// that exist only in both sets.
+	//
+	// Note that the argument to Intersect
+	// must be of the same type as the receiver
+	// of the method. Otherwise, Intersect will
+	// panic.
+	Intersect(other Set) Set
+
+	// Determines if every element in this set is in
+	// the other set but the two sets are not equal.
+	//
+	// Note that the argument to IsProperSubset
+	// must be of the same type as the receiver
+	// of the method. Otherwise, IsProperSubset
+	// will panic.
+	IsProperSubset(other Set) bool
+
+	// Determines if every element in the other set
+	// is in this set but the two sets are not
+	// equal.
+	//
+	// Note that the argument to IsSuperset
+	// must be of the same type as the receiver
+	// of the method. Otherwise, IsSuperset will
+	// panic.
+	IsProperSuperset(other Set) bool
+
+	// Determines if every element in this set is in
+	// the other set.
+	//
+	// Note that the argument to IsSubset
+	// must be of the same type as the receiver
+	// of the method. Otherwise, IsSubset will
+	// panic.
+	IsSubset(other Set) bool
+
+	// Determines if every element in the other set
+	// is in this set.
+	//
+	// Note that the argument to IsSuperset
+	// must be of the same type as the receiver
+	// of the method. Otherwise, IsSuperset will
+	// panic.
+	IsSuperset(other Set) bool
+
+	// Iterates over elements and executes the passed func against each element.
+	// If passed func returns true, stop iteration at the time.
+	Each(func(interface{}) bool)
+
+	// Returns a channel of elements that you can
+	// range over.
+	Iter() <-chan interface{}
+
+	// Returns an Iterator object that you can
+	// use to range over the set.
+	Iterator() *Iterator
+
+	// Remove a single element from the set.
+	Remove(i interface{})
+
+	// Provides a convenient string representation
+	// of the current state of the set.
+	String() string
+
+	// Returns a new set with all elements which are
+	// in either this set or the other set but not in both.
+	//
+	// Note that the argument to SymmetricDifference
+	// must be of the same type as the receiver
+	// of the method. Otherwise, SymmetricDifference
+	// will panic.
+	SymmetricDifference(other Set) Set
+
+	// Returns a new set with all elements in both sets.
+	//
+	// Note that the argument to Union must be of the
+
+	// same type as the receiver of the method.
+	// Otherwise, IsSuperset will panic.
+	Union(other Set) Set
+
+	// Pop removes and returns an arbitrary item from the set.
+	Pop() interface{}
+
+	// Returns all subsets of a given set (Power Set).
+	PowerSet() Set
+
+	// Returns the Cartesian Product of two sets.
+	CartesianProduct(other Set) Set
+
+	// Returns the members of the set as a slice.
+	ToSlice() []interface{}
+}
+
+// NewSet creates and returns a reference to an empty set.  Operations
+// on the resulting set are thread-safe.
+func NewSet(s ...interface{}) Set {
+	set := newThreadSafeSet()
+	for _, item := range s {
+		set.Add(item)
+	}
+	return &set
+}
+
+// NewSetWith creates and returns a new set with the given elements.
+// Operations on the resulting set are thread-safe.
+func NewSetWith(elts ...interface{}) Set {
+	return NewSetFromSlice(elts)
+}
+
+// NewSetFromSlice creates and returns a reference to a set from an
+// existing slice.  Operations on the resulting set are thread-safe.
+func NewSetFromSlice(s []interface{}) Set {
+	a := NewSet(s...)
+	return a
+}
+
+// NewThreadUnsafeSet creates and returns a reference to an empty set.
+// Operations on the resulting set are not thread-safe.
+func NewThreadUnsafeSet() Set {
+	set := newThreadUnsafeSet()
+	return &set
+}
+
+// NewThreadUnsafeSetFromSlice creates and returns a reference to a
+// set from an existing slice.  Operations on the resulting set are
+// not thread-safe.
+func NewThreadUnsafeSetFromSlice(s []interface{}) Set {
+	a := NewThreadUnsafeSet()
+	for _, item := range s {
+		a.Add(item)
+	}
+	return a
+}