diff --git a/vendor/golang.org/x/text/collate/build/builder.go b/vendor/golang.org/x/text/collate/build/builder.go
new file mode 100644
index 0000000..1104284
--- /dev/null
+++ b/vendor/golang.org/x/text/collate/build/builder.go
@@ -0,0 +1,702 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package build // import "golang.org/x/text/collate/build"
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"sort"
+	"strings"
+	"unicode/utf8"
+
+	"golang.org/x/text/internal/colltab"
+	"golang.org/x/text/language"
+	"golang.org/x/text/unicode/norm"
+)
+
+// TODO: optimizations:
+// - expandElem is currently 20K. By putting unique colElems in a separate
+//   table and having a byte array of indexes into this table, we can reduce
+//   the total size to about 7K. By also factoring out the length bytes, we
+//   can reduce this to about 6K.
+// - trie valueBlocks are currently 100K. There are a lot of sparse blocks
+//   and many consecutive values with the same stride. This can be further
+//   compacted.
+// - Compress secondary weights into 8 bits.
+// - Some LDML specs specify a context element. Currently we simply concatenate
+//   those.  Context can be implemented using the contraction trie. If Builder
+//   could analyze and detect when using a context makes sense, there is no
+//   need to expose this construct in the API.
+
+// A Builder builds a root collation table.  The user must specify the
+// collation elements for each entry.  A common use will be to base the weights
+// on those specified in the allkeys* file as provided by the UCA or CLDR.
+type Builder struct {
+	index  *trieBuilder
+	root   ordering
+	locale []*Tailoring
+	t      *table
+	err    error
+	built  bool
+
+	minNonVar int // lowest primary recorded for a variable
+	varTop    int // highest primary recorded for a non-variable
+
+	// indexes used for reusing expansions and contractions
+	expIndex map[string]int      // positions of expansions keyed by their string representation
+	ctHandle map[string]ctHandle // contraction handles keyed by a concatenation of the suffixes
+	ctElem   map[string]int      // contraction elements keyed by their string representation
+}
+
+// A Tailoring builds a collation table based on another collation table.
+// The table is defined by specifying tailorings to the underlying table.
+// See http://unicode.org/reports/tr35/ for an overview of tailoring
+// collation tables.  The CLDR contains pre-defined tailorings for a variety
+// of languages (See http://www.unicode.org/Public/cldr/<version>/core.zip.)
+type Tailoring struct {
+	id      string
+	builder *Builder
+	index   *ordering
+
+	anchor *entry
+	before bool
+}
+
+// NewBuilder returns a new Builder.
+func NewBuilder() *Builder {
+	return &Builder{
+		index:    newTrieBuilder(),
+		root:     makeRootOrdering(),
+		expIndex: make(map[string]int),
+		ctHandle: make(map[string]ctHandle),
+		ctElem:   make(map[string]int),
+	}
+}
+
+// Tailoring returns a Tailoring for the given locale.  One should
+// have completed all calls to Add before calling Tailoring.
+func (b *Builder) Tailoring(loc language.Tag) *Tailoring {
+	t := &Tailoring{
+		id:      loc.String(),
+		builder: b,
+		index:   b.root.clone(),
+	}
+	t.index.id = t.id
+	b.locale = append(b.locale, t)
+	return t
+}
+
+// Add adds an entry to the collation element table, mapping
+// a slice of runes to a sequence of collation elements.
+// A collation element is specified as list of weights: []int{primary, secondary, ...}.
+// The entries are typically obtained from a collation element table
+// as defined in http://www.unicode.org/reports/tr10/#Data_Table_Format.
+// Note that the collation elements specified by colelems are only used
+// as a guide.  The actual weights generated by Builder may differ.
+// The argument variables is a list of indices into colelems that should contain
+// a value for each colelem that is a variable. (See the reference above.)
+func (b *Builder) Add(runes []rune, colelems [][]int, variables []int) error {
+	str := string(runes)
+	elems := make([]rawCE, len(colelems))
+	for i, ce := range colelems {
+		if len(ce) == 0 {
+			break
+		}
+		elems[i] = makeRawCE(ce, 0)
+		if len(ce) == 1 {
+			elems[i].w[1] = defaultSecondary
+		}
+		if len(ce) <= 2 {
+			elems[i].w[2] = defaultTertiary
+		}
+		if len(ce) <= 3 {
+			elems[i].w[3] = ce[0]
+		}
+	}
+	for i, ce := range elems {
+		p := ce.w[0]
+		isvar := false
+		for _, j := range variables {
+			if i == j {
+				isvar = true
+			}
+		}
+		if isvar {
+			if p >= b.minNonVar && b.minNonVar > 0 {
+				return fmt.Errorf("primary value %X of variable is larger than the smallest non-variable %X", p, b.minNonVar)
+			}
+			if p > b.varTop {
+				b.varTop = p
+			}
+		} else if p > 1 { // 1 is a special primary value reserved for FFFE
+			if p <= b.varTop {
+				return fmt.Errorf("primary value %X of non-variable is smaller than the highest variable %X", p, b.varTop)
+			}
+			if b.minNonVar == 0 || p < b.minNonVar {
+				b.minNonVar = p
+			}
+		}
+	}
+	elems, err := convertLargeWeights(elems)
+	if err != nil {
+		return err
+	}
+	cccs := []uint8{}
+	nfd := norm.NFD.String(str)
+	for i := range nfd {
+		cccs = append(cccs, norm.NFD.PropertiesString(nfd[i:]).CCC())
+	}
+	if len(cccs) < len(elems) {
+		if len(cccs) > 2 {
+			return fmt.Errorf("number of decomposed characters should be greater or equal to the number of collation elements for len(colelems) > 3 (%d < %d)", len(cccs), len(elems))
+		}
+		p := len(elems) - 1
+		for ; p > 0 && elems[p].w[0] == 0; p-- {
+			elems[p].ccc = cccs[len(cccs)-1]
+		}
+		for ; p >= 0; p-- {
+			elems[p].ccc = cccs[0]
+		}
+	} else {
+		for i := range elems {
+			elems[i].ccc = cccs[i]
+		}
+	}
+	// doNorm in collate.go assumes that the following conditions hold.
+	if len(elems) > 1 && len(cccs) > 1 && cccs[0] != 0 && cccs[0] != cccs[len(cccs)-1] {
+		return fmt.Errorf("incompatible CCC values for expansion %X (%d)", runes, cccs)
+	}
+	b.root.newEntry(str, elems)
+	return nil
+}
+
+func (t *Tailoring) setAnchor(anchor string) error {
+	anchor = norm.NFC.String(anchor)
+	a := t.index.find(anchor)
+	if a == nil {
+		a = t.index.newEntry(anchor, nil)
+		a.implicit = true
+		a.modified = true
+		for _, r := range []rune(anchor) {
+			e := t.index.find(string(r))
+			e.lock = true
+		}
+	}
+	t.anchor = a
+	return nil
+}
+
+// SetAnchor sets the point after which elements passed in subsequent calls to
+// Insert will be inserted.  It is equivalent to the reset directive in an LDML
+// specification.  See Insert for an example.
+// SetAnchor supports the following logical reset positions:
+// <first_tertiary_ignorable/>, <last_teriary_ignorable/>, <first_primary_ignorable/>,
+// and <last_non_ignorable/>.
+func (t *Tailoring) SetAnchor(anchor string) error {
+	if err := t.setAnchor(anchor); err != nil {
+		return err
+	}
+	t.before = false
+	return nil
+}
+
+// SetAnchorBefore is similar to SetAnchor, except that subsequent calls to
+// Insert will insert entries before the anchor.
+func (t *Tailoring) SetAnchorBefore(anchor string) error {
+	if err := t.setAnchor(anchor); err != nil {
+		return err
+	}
+	t.before = true
+	return nil
+}
+
+// Insert sets the ordering of str relative to the entry set by the previous
+// call to SetAnchor or Insert.  The argument extend corresponds
+// to the extend elements as defined in LDML.  A non-empty value for extend
+// will cause the collation elements corresponding to extend to be appended
+// to the collation elements generated for the entry added by Insert.
+// This has the same net effect as sorting str after the string anchor+extend.
+// See http://www.unicode.org/reports/tr10/#Tailoring_Example for details
+// on parametric tailoring and http://unicode.org/reports/tr35/#Collation_Elements
+// for full details on LDML.
+//
+// Examples: create a tailoring for Swedish, where "ä" is ordered after "z"
+// at the primary sorting level:
+//      t := b.Tailoring("se")
+// 		t.SetAnchor("z")
+// 		t.Insert(colltab.Primary, "ä", "")
+// Order "ü" after "ue" at the secondary sorting level:
+//		t.SetAnchor("ue")
+//		t.Insert(colltab.Secondary, "ü","")
+// or
+//		t.SetAnchor("u")
+//		t.Insert(colltab.Secondary, "ü", "e")
+// Order "q" afer "ab" at the secondary level and "Q" after "q"
+// at the tertiary level:
+// 		t.SetAnchor("ab")
+// 		t.Insert(colltab.Secondary, "q", "")
+// 		t.Insert(colltab.Tertiary, "Q", "")
+// Order "b" before "a":
+//      t.SetAnchorBefore("a")
+//      t.Insert(colltab.Primary, "b", "")
+// Order "0" after the last primary ignorable:
+//      t.SetAnchor("<last_primary_ignorable/>")
+//      t.Insert(colltab.Primary, "0", "")
+func (t *Tailoring) Insert(level colltab.Level, str, extend string) error {
+	if t.anchor == nil {
+		return fmt.Errorf("%s:Insert: no anchor point set for tailoring of %s", t.id, str)
+	}
+	str = norm.NFC.String(str)
+	e := t.index.find(str)
+	if e == nil {
+		e = t.index.newEntry(str, nil)
+	} else if e.logical != noAnchor {
+		return fmt.Errorf("%s:Insert: cannot reinsert logical reset position %q", t.id, e.str)
+	}
+	if e.lock {
+		return fmt.Errorf("%s:Insert: cannot reinsert element %q", t.id, e.str)
+	}
+	a := t.anchor
+	// Find the first element after the anchor which differs at a level smaller or
+	// equal to the given level.  Then insert at this position.
+	// See http://unicode.org/reports/tr35/#Collation_Elements, Section 5.14.5 for details.
+	e.before = t.before
+	if t.before {
+		t.before = false
+		if a.prev == nil {
+			a.insertBefore(e)
+		} else {
+			for a = a.prev; a.level > level; a = a.prev {
+			}
+			a.insertAfter(e)
+		}
+		e.level = level
+	} else {
+		for ; a.level > level; a = a.next {
+		}
+		e.level = a.level
+		if a != e {
+			a.insertAfter(e)
+			a.level = level
+		} else {
+			// We don't set a to prev itself. This has the effect of the entry
+			// getting new collation elements that are an increment of itself.
+			// This is intentional.
+			a.prev.level = level
+		}
+	}
+	e.extend = norm.NFD.String(extend)
+	e.exclude = false
+	e.modified = true
+	e.elems = nil
+	t.anchor = e
+	return nil
+}
+
+func (o *ordering) getWeight(e *entry) []rawCE {
+	if len(e.elems) == 0 && e.logical == noAnchor {
+		if e.implicit {
+			for _, r := range e.runes {
+				e.elems = append(e.elems, o.getWeight(o.find(string(r)))...)
+			}
+		} else if e.before {
+			count := [colltab.Identity + 1]int{}
+			a := e
+			for ; a.elems == nil && !a.implicit; a = a.next {
+				count[a.level]++
+			}
+			e.elems = []rawCE{makeRawCE(a.elems[0].w, a.elems[0].ccc)}
+			for i := colltab.Primary; i < colltab.Quaternary; i++ {
+				if count[i] != 0 {
+					e.elems[0].w[i] -= count[i]
+					break
+				}
+			}
+			if e.prev != nil {
+				o.verifyWeights(e.prev, e, e.prev.level)
+			}
+		} else {
+			prev := e.prev
+			e.elems = nextWeight(prev.level, o.getWeight(prev))
+			o.verifyWeights(e, e.next, e.level)
+		}
+	}
+	return e.elems
+}
+
+func (o *ordering) addExtension(e *entry) {
+	if ex := o.find(e.extend); ex != nil {
+		e.elems = append(e.elems, ex.elems...)
+	} else {
+		for _, r := range []rune(e.extend) {
+			e.elems = append(e.elems, o.find(string(r)).elems...)
+		}
+	}
+	e.extend = ""
+}
+
+func (o *ordering) verifyWeights(a, b *entry, level colltab.Level) error {
+	if level == colltab.Identity || b == nil || b.elems == nil || a.elems == nil {
+		return nil
+	}
+	for i := colltab.Primary; i < level; i++ {
+		if a.elems[0].w[i] < b.elems[0].w[i] {
+			return nil
+		}
+	}
+	if a.elems[0].w[level] >= b.elems[0].w[level] {
+		err := fmt.Errorf("%s:overflow: collation elements of %q (%X) overflows those of %q (%X) at level %d (%X >= %X)", o.id, a.str, a.runes, b.str, b.runes, level, a.elems, b.elems)
+		log.Println(err)
+		// TODO: return the error instead, or better, fix the conflicting entry by making room.
+	}
+	return nil
+}
+
+func (b *Builder) error(e error) {
+	if e != nil {
+		b.err = e
+	}
+}
+
+func (b *Builder) errorID(locale string, e error) {
+	if e != nil {
+		b.err = fmt.Errorf("%s:%v", locale, e)
+	}
+}
+
+// patchNorm ensures that NFC and NFD counterparts are consistent.
+func (o *ordering) patchNorm() {
+	// Insert the NFD counterparts, if necessary.
+	for _, e := range o.ordered {
+		nfd := norm.NFD.String(e.str)
+		if nfd != e.str {
+			if e0 := o.find(nfd); e0 != nil && !e0.modified {
+				e0.elems = e.elems
+			} else if e.modified && !equalCEArrays(o.genColElems(nfd), e.elems) {
+				e := o.newEntry(nfd, e.elems)
+				e.modified = true
+			}
+		}
+	}
+	// Update unchanged composed forms if one of their parts changed.
+	for _, e := range o.ordered {
+		nfd := norm.NFD.String(e.str)
+		if e.modified || nfd == e.str {
+			continue
+		}
+		if e0 := o.find(nfd); e0 != nil {
+			e.elems = e0.elems
+		} else {
+			e.elems = o.genColElems(nfd)
+			if norm.NFD.LastBoundary([]byte(nfd)) == 0 {
+				r := []rune(nfd)
+				head := string(r[0])
+				tail := ""
+				for i := 1; i < len(r); i++ {
+					s := norm.NFC.String(head + string(r[i]))
+					if e0 := o.find(s); e0 != nil && e0.modified {
+						head = s
+					} else {
+						tail += string(r[i])
+					}
+				}
+				e.elems = append(o.genColElems(head), o.genColElems(tail)...)
+			}
+		}
+	}
+	// Exclude entries for which the individual runes generate the same collation elements.
+	for _, e := range o.ordered {
+		if len(e.runes) > 1 && equalCEArrays(o.genColElems(e.str), e.elems) {
+			e.exclude = true
+		}
+	}
+}
+
+func (b *Builder) buildOrdering(o *ordering) {
+	for _, e := range o.ordered {
+		o.getWeight(e)
+	}
+	for _, e := range o.ordered {
+		o.addExtension(e)
+	}
+	o.patchNorm()
+	o.sort()
+	simplify(o)
+	b.processExpansions(o)   // requires simplify
+	b.processContractions(o) // requires simplify
+
+	t := newNode()
+	for e := o.front(); e != nil; e, _ = e.nextIndexed() {
+		if !e.skip() {
+			ce, err := e.encode()
+			b.errorID(o.id, err)
+			t.insert(e.runes[0], ce)
+		}
+	}
+	o.handle = b.index.addTrie(t)
+}
+
+func (b *Builder) build() (*table, error) {
+	if b.built {
+		return b.t, b.err
+	}
+	b.built = true
+	b.t = &table{
+		Table: colltab.Table{
+			MaxContractLen: utf8.UTFMax,
+			VariableTop:    uint32(b.varTop),
+		},
+	}
+
+	b.buildOrdering(&b.root)
+	b.t.root = b.root.handle
+	for _, t := range b.locale {
+		b.buildOrdering(t.index)
+		if b.err != nil {
+			break
+		}
+	}
+	i, err := b.index.generate()
+	b.t.trie = *i
+	b.t.Index = colltab.Trie{
+		Index:   i.index,
+		Values:  i.values,
+		Index0:  i.index[blockSize*b.t.root.lookupStart:],
+		Values0: i.values[blockSize*b.t.root.valueStart:],
+	}
+	b.error(err)
+	return b.t, b.err
+}
+
+// Build builds the root Collator.
+func (b *Builder) Build() (colltab.Weighter, error) {
+	table, err := b.build()
+	if err != nil {
+		return nil, err
+	}
+	return table, nil
+}
+
+// Build builds a Collator for Tailoring t.
+func (t *Tailoring) Build() (colltab.Weighter, error) {
+	// TODO: implement.
+	return nil, nil
+}
+
+// Print prints the tables for b and all its Tailorings as a Go file
+// that can be included in the Collate package.
+func (b *Builder) Print(w io.Writer) (n int, err error) {
+	p := func(nn int, e error) {
+		n += nn
+		if err == nil {
+			err = e
+		}
+	}
+	t, err := b.build()
+	if err != nil {
+		return 0, err
+	}
+	p(fmt.Fprintf(w, `var availableLocales = "und`))
+	for _, loc := range b.locale {
+		if loc.id != "und" {
+			p(fmt.Fprintf(w, ",%s", loc.id))
+		}
+	}
+	p(fmt.Fprint(w, "\"\n\n"))
+	p(fmt.Fprintf(w, "const varTop = 0x%x\n\n", b.varTop))
+	p(fmt.Fprintln(w, "var locales = [...]tableIndex{"))
+	for _, loc := range b.locale {
+		if loc.id == "und" {
+			p(t.fprintIndex(w, loc.index.handle, loc.id))
+		}
+	}
+	for _, loc := range b.locale {
+		if loc.id != "und" {
+			p(t.fprintIndex(w, loc.index.handle, loc.id))
+		}
+	}
+	p(fmt.Fprint(w, "}\n\n"))
+	n, _, err = t.fprint(w, "main")
+	return
+}
+
+// reproducibleFromNFKD checks whether the given expansion could be generated
+// from an NFKD expansion.
+func reproducibleFromNFKD(e *entry, exp, nfkd []rawCE) bool {
+	// Length must be equal.
+	if len(exp) != len(nfkd) {
+		return false
+	}
+	for i, ce := range exp {
+		// Primary and secondary values should be equal.
+		if ce.w[0] != nfkd[i].w[0] || ce.w[1] != nfkd[i].w[1] {
+			return false
+		}
+		// Tertiary values should be equal to maxTertiary for third element onwards.
+		// TODO: there seem to be a lot of cases in CLDR (e.g. ㏭ in zh.xml) that can
+		// simply be dropped.  Try this out by dropping the following code.
+		if i >= 2 && ce.w[2] != maxTertiary {
+			return false
+		}
+		if _, err := makeCE(ce); err != nil {
+			// Simply return false. The error will be caught elsewhere.
+			return false
+		}
+	}
+	return true
+}
+
+func simplify(o *ordering) {
+	// Runes that are a starter of a contraction should not be removed.
+	// (To date, there is only Kannada character 0CCA.)
+	keep := make(map[rune]bool)
+	for e := o.front(); e != nil; e, _ = e.nextIndexed() {
+		if len(e.runes) > 1 {
+			keep[e.runes[0]] = true
+		}
+	}
+	// Tag entries for which the runes NFKD decompose to identical values.
+	for e := o.front(); e != nil; e, _ = e.nextIndexed() {
+		s := e.str
+		nfkd := norm.NFKD.String(s)
+		nfd := norm.NFD.String(s)
+		if e.decompose || len(e.runes) > 1 || len(e.elems) == 1 || keep[e.runes[0]] || nfkd == nfd {
+			continue
+		}
+		if reproducibleFromNFKD(e, e.elems, o.genColElems(nfkd)) {
+			e.decompose = true
+		}
+	}
+}
+
+// appendExpansion converts the given collation sequence to
+// collation elements and adds them to the expansion table.
+// It returns an index to the expansion table.
+func (b *Builder) appendExpansion(e *entry) int {
+	t := b.t
+	i := len(t.ExpandElem)
+	ce := uint32(len(e.elems))
+	t.ExpandElem = append(t.ExpandElem, ce)
+	for _, w := range e.elems {
+		ce, err := makeCE(w)
+		if err != nil {
+			b.error(err)
+			return -1
+		}
+		t.ExpandElem = append(t.ExpandElem, ce)
+	}
+	return i
+}
+
+// processExpansions extracts data necessary to generate
+// the extraction tables.
+func (b *Builder) processExpansions(o *ordering) {
+	for e := o.front(); e != nil; e, _ = e.nextIndexed() {
+		if !e.expansion() {
+			continue
+		}
+		key := fmt.Sprintf("%v", e.elems)
+		i, ok := b.expIndex[key]
+		if !ok {
+			i = b.appendExpansion(e)
+			b.expIndex[key] = i
+		}
+		e.expansionIndex = i
+	}
+}
+
+func (b *Builder) processContractions(o *ordering) {
+	// Collate contractions per starter rune.
+	starters := []rune{}
+	cm := make(map[rune][]*entry)
+	for e := o.front(); e != nil; e, _ = e.nextIndexed() {
+		if e.contraction() {
+			if len(e.str) > b.t.MaxContractLen {
+				b.t.MaxContractLen = len(e.str)
+			}
+			r := e.runes[0]
+			if _, ok := cm[r]; !ok {
+				starters = append(starters, r)
+			}
+			cm[r] = append(cm[r], e)
+		}
+	}
+	// Add entries of single runes that are at a start of a contraction.
+	for e := o.front(); e != nil; e, _ = e.nextIndexed() {
+		if !e.contraction() {
+			r := e.runes[0]
+			if _, ok := cm[r]; ok {
+				cm[r] = append(cm[r], e)
+			}
+		}
+	}
+	// Build the tries for the contractions.
+	t := b.t
+	for _, r := range starters {
+		l := cm[r]
+		// Compute suffix strings. There are 31 different contraction suffix
+		// sets for 715 contractions and 82 contraction starter runes as of
+		// version 6.0.0.
+		sufx := []string{}
+		hasSingle := false
+		for _, e := range l {
+			if len(e.runes) > 1 {
+				sufx = append(sufx, string(e.runes[1:]))
+			} else {
+				hasSingle = true
+			}
+		}
+		if !hasSingle {
+			b.error(fmt.Errorf("no single entry for starter rune %U found", r))
+			continue
+		}
+		// Unique the suffix set.
+		sort.Strings(sufx)
+		key := strings.Join(sufx, "\n")
+		handle, ok := b.ctHandle[key]
+		if !ok {
+			var err error
+			handle, err = appendTrie(&t.ContractTries, sufx)
+			if err != nil {
+				b.error(err)
+			}
+			b.ctHandle[key] = handle
+		}
+		// Bucket sort entries in index order.
+		es := make([]*entry, len(l))
+		for _, e := range l {
+			var p, sn int
+			if len(e.runes) > 1 {
+				str := []byte(string(e.runes[1:]))
+				p, sn = lookup(&t.ContractTries, handle, str)
+				if sn != len(str) {
+					log.Fatalf("%s: processContractions: unexpected length for '%X'; len=%d; want %d", o.id, e.runes, sn, len(str))
+				}
+			}
+			if es[p] != nil {
+				log.Fatalf("%s: multiple contractions for position %d for rune %U", o.id, p, e.runes[0])
+			}
+			es[p] = e
+		}
+		// Create collation elements for contractions.
+		elems := []uint32{}
+		for _, e := range es {
+			ce, err := e.encodeBase()
+			b.errorID(o.id, err)
+			elems = append(elems, ce)
+		}
+		key = fmt.Sprintf("%v", elems)
+		i, ok := b.ctElem[key]
+		if !ok {
+			i = len(t.ContractElem)
+			b.ctElem[key] = i
+			t.ContractElem = append(t.ContractElem, elems...)
+		}
+		// Store info in entry for starter rune.
+		es[0].contractionIndex = i
+		es[0].contractionHandle = handle
+	}
+}
diff --git a/vendor/golang.org/x/text/collate/build/colelem.go b/vendor/golang.org/x/text/collate/build/colelem.go
new file mode 100644
index 0000000..726fe54
--- /dev/null
+++ b/vendor/golang.org/x/text/collate/build/colelem.go
@@ -0,0 +1,294 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package build
+
+import (
+	"fmt"
+	"unicode"
+
+	"golang.org/x/text/internal/colltab"
+)
+
+const (
+	defaultSecondary = 0x20
+	defaultTertiary  = 0x2
+	maxTertiary      = 0x1F
+)
+
+type rawCE struct {
+	w   []int
+	ccc uint8
+}
+
+func makeRawCE(w []int, ccc uint8) rawCE {
+	ce := rawCE{w: make([]int, 4), ccc: ccc}
+	copy(ce.w, w)
+	return ce
+}
+
+// A collation element is represented as an uint32.
+// In the typical case, a rune maps to a single collation element. If a rune
+// can be the start of a contraction or expands into multiple collation elements,
+// then the collation element that is associated with a rune will have a special
+// form to represent such m to n mappings.  Such special collation elements
+// have a value >= 0x80000000.
+
+const (
+	maxPrimaryBits   = 21
+	maxSecondaryBits = 12
+	maxTertiaryBits  = 8
+)
+
+func makeCE(ce rawCE) (uint32, error) {
+	v, e := colltab.MakeElem(ce.w[0], ce.w[1], ce.w[2], ce.ccc)
+	return uint32(v), e
+}
+
+// For contractions, collation elements are of the form
+// 110bbbbb bbbbbbbb iiiiiiii iiiinnnn, where
+//   - n* is the size of the first node in the contraction trie.
+//   - i* is the index of the first node in the contraction trie.
+//   - b* is the offset into the contraction collation element table.
+// See contract.go for details on the contraction trie.
+const (
+	contractID            = 0xC0000000
+	maxNBits              = 4
+	maxTrieIndexBits      = 12
+	maxContractOffsetBits = 13
+)
+
+func makeContractIndex(h ctHandle, offset int) (uint32, error) {
+	if h.n >= 1<<maxNBits {
+		return 0, fmt.Errorf("size of contraction trie node too large: %d >= %d", h.n, 1<<maxNBits)
+	}
+	if h.index >= 1<<maxTrieIndexBits {
+		return 0, fmt.Errorf("size of contraction trie offset too large: %d >= %d", h.index, 1<<maxTrieIndexBits)
+	}
+	if offset >= 1<<maxContractOffsetBits {
+		return 0, fmt.Errorf("contraction offset out of bounds: %x >= %x", offset, 1<<maxContractOffsetBits)
+	}
+	ce := uint32(contractID)
+	ce += uint32(offset << (maxNBits + maxTrieIndexBits))
+	ce += uint32(h.index << maxNBits)
+	ce += uint32(h.n)
+	return ce, nil
+}
+
+// For expansions, collation elements are of the form
+// 11100000 00000000 bbbbbbbb bbbbbbbb,
+// where b* is the index into the expansion sequence table.
+const (
+	expandID           = 0xE0000000
+	maxExpandIndexBits = 16
+)
+
+func makeExpandIndex(index int) (uint32, error) {
+	if index >= 1<<maxExpandIndexBits {
+		return 0, fmt.Errorf("expansion index out of bounds: %x >= %x", index, 1<<maxExpandIndexBits)
+	}
+	return expandID + uint32(index), nil
+}
+
+// Each list of collation elements corresponding to an expansion starts with
+// a header indicating the length of the sequence.
+func makeExpansionHeader(n int) (uint32, error) {
+	return uint32(n), nil
+}
+
+// Some runes can be expanded using NFKD decomposition. Instead of storing the full
+// sequence of collation elements, we decompose the rune and lookup the collation
+// elements for each rune in the decomposition and modify the tertiary weights.
+// The collation element, in this case, is of the form
+// 11110000 00000000 wwwwwwww vvvvvvvv, where
+//   - v* is the replacement tertiary weight for the first rune,
+//   - w* is the replacement tertiary weight for the second rune,
+// Tertiary weights of subsequent runes should be replaced with maxTertiary.
+// See http://www.unicode.org/reports/tr10/#Compatibility_Decompositions for more details.
+const (
+	decompID = 0xF0000000
+)
+
+func makeDecompose(t1, t2 int) (uint32, error) {
+	if t1 >= 256 || t1 < 0 {
+		return 0, fmt.Errorf("first tertiary weight out of bounds: %d >= 256", t1)
+	}
+	if t2 >= 256 || t2 < 0 {
+		return 0, fmt.Errorf("second tertiary weight out of bounds: %d >= 256", t2)
+	}
+	return uint32(t2<<8+t1) + decompID, nil
+}
+
+const (
+	// These constants were taken from http://www.unicode.org/versions/Unicode6.0.0/ch12.pdf.
+	minUnified       rune = 0x4E00
+	maxUnified            = 0x9FFF
+	minCompatibility      = 0xF900
+	maxCompatibility      = 0xFAFF
+	minRare               = 0x3400
+	maxRare               = 0x4DBF
+)
+const (
+	commonUnifiedOffset = 0x10000
+	rareUnifiedOffset   = 0x20000 // largest rune in common is U+FAFF
+	otherOffset         = 0x50000 // largest rune in rare is U+2FA1D
+	illegalOffset       = otherOffset + int(unicode.MaxRune)
+	maxPrimary          = illegalOffset + 1
+)
+
+// implicitPrimary returns the primary weight for the a rune
+// for which there is no entry for the rune in the collation table.
+// We take a different approach from the one specified in
+// http://unicode.org/reports/tr10/#Implicit_Weights,
+// but preserve the resulting relative ordering of the runes.
+func implicitPrimary(r rune) int {
+	if unicode.Is(unicode.Ideographic, r) {
+		if r >= minUnified && r <= maxUnified {
+			// The most common case for CJK.
+			return int(r) + commonUnifiedOffset
+		}
+		if r >= minCompatibility && r <= maxCompatibility {
+			// This will typically not hit. The DUCET explicitly specifies mappings
+			// for all characters that do not decompose.
+			return int(r) + commonUnifiedOffset
+		}
+		return int(r) + rareUnifiedOffset
+	}
+	return int(r) + otherOffset
+}
+
+// convertLargeWeights converts collation elements with large
+// primaries (either double primaries or for illegal runes)
+// to our own representation.
+// A CJK character C is represented in the DUCET as
+//   [.FBxx.0020.0002.C][.BBBB.0000.0000.C]
+// We will rewrite these characters to a single CE.
+// We assume the CJK values start at 0x8000.
+// See http://unicode.org/reports/tr10/#Implicit_Weights
+func convertLargeWeights(elems []rawCE) (res []rawCE, err error) {
+	const (
+		cjkPrimaryStart   = 0xFB40
+		rarePrimaryStart  = 0xFB80
+		otherPrimaryStart = 0xFBC0
+		illegalPrimary    = 0xFFFE
+		highBitsMask      = 0x3F
+		lowBitsMask       = 0x7FFF
+		lowBitsFlag       = 0x8000
+		shiftBits         = 15
+	)
+	for i := 0; i < len(elems); i++ {
+		ce := elems[i].w
+		p := ce[0]
+		if p < cjkPrimaryStart {
+			continue
+		}
+		if p > 0xFFFF {
+			return elems, fmt.Errorf("found primary weight %X; should be <= 0xFFFF", p)
+		}
+		if p >= illegalPrimary {
+			ce[0] = illegalOffset + p - illegalPrimary
+		} else {
+			if i+1 >= len(elems) {
+				return elems, fmt.Errorf("second part of double primary weight missing: %v", elems)
+			}
+			if elems[i+1].w[0]&lowBitsFlag == 0 {
+				return elems, fmt.Errorf("malformed second part of double primary weight: %v", elems)
+			}
+			np := ((p & highBitsMask) << shiftBits) + elems[i+1].w[0]&lowBitsMask
+			switch {
+			case p < rarePrimaryStart:
+				np += commonUnifiedOffset
+			case p < otherPrimaryStart:
+				np += rareUnifiedOffset
+			default:
+				p += otherOffset
+			}
+			ce[0] = np
+			for j := i + 1; j+1 < len(elems); j++ {
+				elems[j] = elems[j+1]
+			}
+			elems = elems[:len(elems)-1]
+		}
+	}
+	return elems, nil
+}
+
+// nextWeight computes the first possible collation weights following elems
+// for the given level.
+func nextWeight(level colltab.Level, elems []rawCE) []rawCE {
+	if level == colltab.Identity {
+		next := make([]rawCE, len(elems))
+		copy(next, elems)
+		return next
+	}
+	next := []rawCE{makeRawCE(elems[0].w, elems[0].ccc)}
+	next[0].w[level]++
+	if level < colltab.Secondary {
+		next[0].w[colltab.Secondary] = defaultSecondary
+	}
+	if level < colltab.Tertiary {
+		next[0].w[colltab.Tertiary] = defaultTertiary
+	}
+	// Filter entries that cannot influence ordering.
+	for _, ce := range elems[1:] {
+		skip := true
+		for i := colltab.Primary; i < level; i++ {
+			skip = skip && ce.w[i] == 0
+		}
+		if !skip {
+			next = append(next, ce)
+		}
+	}
+	return next
+}
+
+func nextVal(elems []rawCE, i int, level colltab.Level) (index, value int) {
+	for ; i < len(elems) && elems[i].w[level] == 0; i++ {
+	}
+	if i < len(elems) {
+		return i, elems[i].w[level]
+	}
+	return i, 0
+}
+
+// compareWeights returns -1 if a < b, 1 if a > b, or 0 otherwise.
+// It also returns the collation level at which the difference is found.
+func compareWeights(a, b []rawCE) (result int, level colltab.Level) {
+	for level := colltab.Primary; level < colltab.Identity; level++ {
+		var va, vb int
+		for ia, ib := 0, 0; ia < len(a) || ib < len(b); ia, ib = ia+1, ib+1 {
+			ia, va = nextVal(a, ia, level)
+			ib, vb = nextVal(b, ib, level)
+			if va != vb {
+				if va < vb {
+					return -1, level
+				} else {
+					return 1, level
+				}
+			}
+		}
+	}
+	return 0, colltab.Identity
+}
+
+func equalCE(a, b rawCE) bool {
+	for i := 0; i < 3; i++ {
+		if b.w[i] != a.w[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func equalCEArrays(a, b []rawCE) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if !equalCE(a[i], b[i]) {
+			return false
+		}
+	}
+	return true
+}
diff --git a/vendor/golang.org/x/text/collate/build/contract.go b/vendor/golang.org/x/text/collate/build/contract.go
new file mode 100644
index 0000000..a6a7e01
--- /dev/null
+++ b/vendor/golang.org/x/text/collate/build/contract.go
@@ -0,0 +1,309 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package build
+
+import (
+	"fmt"
+	"io"
+	"reflect"
+	"sort"
+	"strings"
+
+	"golang.org/x/text/internal/colltab"
+)
+
+// This file contains code for detecting contractions and generating
+// the necessary tables.
+// Any Unicode Collation Algorithm (UCA) table entry that has more than
+// one rune one the left-hand side is called a contraction.
+// See http://www.unicode.org/reports/tr10/#Contractions for more details.
+//
+// We define the following terms:
+//   initial:     a rune that appears as the first rune in a contraction.
+//   suffix:      a sequence of runes succeeding the initial rune
+//                in a given contraction.
+//   non-initial: a rune that appears in a suffix.
+//
+// A rune may be both an initial and a non-initial and may be so in
+// many contractions.  An initial may typically also appear by itself.
+// In case of ambiguities, the UCA requires we match the longest
+// contraction.
+//
+// Many contraction rules share the same set of possible suffixes.
+// We store sets of suffixes in a trie that associates an index with
+// each suffix in the set.  This index can be used to look up a
+// collation element associated with the (starter rune, suffix) pair.
+//
+// The trie is defined on a UTF-8 byte sequence.
+// The overall trie is represented as an array of ctEntries.  Each node of the trie
+// is represented as a subsequence of ctEntries, where each entry corresponds to
+// a possible match of a next character in the search string.  An entry
+// also includes the length and offset to the next sequence of entries
+// to check in case of a match.
+
+const (
+	final   = 0
+	noIndex = 0xFF
+)
+
+// ctEntry associates to a matching byte an offset and/or next sequence of
+// bytes to check. A ctEntry c is called final if a match means that the
+// longest suffix has been found.  An entry c is final if c.N == 0.
+// A single final entry can match a range of characters to an offset.
+// A non-final entry always matches a single byte. Note that a non-final
+// entry might still resemble a completed suffix.
+// Examples:
+// The suffix strings "ab" and "ac" can be represented as:
+// []ctEntry{
+//     {'a', 1, 1, noIndex},  // 'a' by itself does not match, so i is 0xFF.
+//     {'b', 'c', 0, 1},   // "ab" -> 1, "ac" -> 2
+// }
+//
+// The suffix strings "ab", "abc", "abd", and "abcd" can be represented as:
+// []ctEntry{
+//     {'a', 1, 1, noIndex}, // 'a' must be followed by 'b'.
+//     {'b', 1, 2, 1},    // "ab" -> 1, may be followed by 'c' or 'd'.
+//     {'d', 'd', final, 3},  // "abd" -> 3
+//     {'c', 4, 1, 2},    // "abc" -> 2, may be followed by 'd'.
+//     {'d', 'd', final, 4},  // "abcd" -> 4
+// }
+// See genStateTests in contract_test.go for more examples.
+type ctEntry struct {
+	L uint8 // non-final: byte value to match; final: lowest match in range.
+	H uint8 // non-final: relative index to next block; final: highest match in range.
+	N uint8 // non-final: length of next block; final: final
+	I uint8 // result offset. Will be noIndex if more bytes are needed to complete.
+}
+
+// contractTrieSet holds a set of contraction tries. The tries are stored
+// consecutively in the entry field.
+type contractTrieSet []struct{ l, h, n, i uint8 }
+
+// ctHandle is used to identify a trie in the trie set, consisting in an offset
+// in the array and the size of the first node.
+type ctHandle struct {
+	index, n int
+}
+
+// appendTrie adds a new trie for the given suffixes to the trie set and returns
+// a handle to it.  The handle will be invalid on error.
+func appendTrie(ct *colltab.ContractTrieSet, suffixes []string) (ctHandle, error) {
+	es := make([]stridx, len(suffixes))
+	for i, s := range suffixes {
+		es[i].str = s
+	}
+	sort.Sort(offsetSort(es))
+	for i := range es {
+		es[i].index = i + 1
+	}
+	sort.Sort(genidxSort(es))
+	i := len(*ct)
+	n, err := genStates(ct, es)
+	if err != nil {
+		*ct = (*ct)[:i]
+		return ctHandle{}, err
+	}
+	return ctHandle{i, n}, nil
+}
+
+// genStates generates ctEntries for a given suffix set and returns
+// the number of entries for the first node.
+func genStates(ct *colltab.ContractTrieSet, sis []stridx) (int, error) {
+	if len(sis) == 0 {
+		return 0, fmt.Errorf("genStates: list of suffices must be non-empty")
+	}
+	start := len(*ct)
+	// create entries for differing first bytes.
+	for _, si := range sis {
+		s := si.str
+		if len(s) == 0 {
+			continue
+		}
+		added := false
+		c := s[0]
+		if len(s) > 1 {
+			for j := len(*ct) - 1; j >= start; j-- {
+				if (*ct)[j].L == c {
+					added = true
+					break
+				}
+			}
+			if !added {
+				*ct = append(*ct, ctEntry{L: c, I: noIndex})
+			}
+		} else {
+			for j := len(*ct) - 1; j >= start; j-- {
+				// Update the offset for longer suffixes with the same byte.
+				if (*ct)[j].L == c {
+					(*ct)[j].I = uint8(si.index)
+					added = true
+				}
+				// Extend range of final ctEntry, if possible.
+				if (*ct)[j].H+1 == c {
+					(*ct)[j].H = c
+					added = true
+				}
+			}
+			if !added {
+				*ct = append(*ct, ctEntry{L: c, H: c, N: final, I: uint8(si.index)})
+			}
+		}
+	}
+	n := len(*ct) - start
+	// Append nodes for the remainder of the suffixes for each ctEntry.
+	sp := 0
+	for i, end := start, len(*ct); i < end; i++ {
+		fe := (*ct)[i]
+		if fe.H == 0 { // uninitialized non-final
+			ln := len(*ct) - start - n
+			if ln > 0xFF {
+				return 0, fmt.Errorf("genStates: relative block offset too large: %d > 255", ln)
+			}
+			fe.H = uint8(ln)
+			// Find first non-final strings with same byte as current entry.
+			for ; sis[sp].str[0] != fe.L; sp++ {
+			}
+			se := sp + 1
+			for ; se < len(sis) && len(sis[se].str) > 1 && sis[se].str[0] == fe.L; se++ {
+			}
+			sl := sis[sp:se]
+			sp = se
+			for i, si := range sl {
+				sl[i].str = si.str[1:]
+			}
+			nn, err := genStates(ct, sl)
+			if err != nil {
+				return 0, err
+			}
+			fe.N = uint8(nn)
+			(*ct)[i] = fe
+		}
+	}
+	sort.Sort(entrySort((*ct)[start : start+n]))
+	return n, nil
+}
+
+// There may be both a final and non-final entry for a byte if the byte
+// is implied in a range of matches in the final entry.
+// We need to ensure that the non-final entry comes first in that case.
+type entrySort colltab.ContractTrieSet
+
+func (fe entrySort) Len() int      { return len(fe) }
+func (fe entrySort) Swap(i, j int) { fe[i], fe[j] = fe[j], fe[i] }
+func (fe entrySort) Less(i, j int) bool {
+	return fe[i].L > fe[j].L
+}
+
+// stridx is used for sorting suffixes and their associated offsets.
+type stridx struct {
+	str   string
+	index int
+}
+
+// For computing the offsets, we first sort by size, and then by string.
+// This ensures that strings that only differ in the last byte by 1
+// are sorted consecutively in increasing order such that they can
+// be packed as a range in a final ctEntry.
+type offsetSort []stridx
+
+func (si offsetSort) Len() int      { return len(si) }
+func (si offsetSort) Swap(i, j int) { si[i], si[j] = si[j], si[i] }
+func (si offsetSort) Less(i, j int) bool {
+	if len(si[i].str) != len(si[j].str) {
+		return len(si[i].str) > len(si[j].str)
+	}
+	return si[i].str < si[j].str
+}
+
+// For indexing, we want to ensure that strings are sorted in string order, where
+// for strings with the same prefix, we put longer strings before shorter ones.
+type genidxSort []stridx
+
+func (si genidxSort) Len() int      { return len(si) }
+func (si genidxSort) Swap(i, j int) { si[i], si[j] = si[j], si[i] }
+func (si genidxSort) Less(i, j int) bool {
+	if strings.HasPrefix(si[j].str, si[i].str) {
+		return false
+	}
+	if strings.HasPrefix(si[i].str, si[j].str) {
+		return true
+	}
+	return si[i].str < si[j].str
+}
+
+// lookup matches the longest suffix in str and returns the associated offset
+// and the number of bytes consumed.
+func lookup(ct *colltab.ContractTrieSet, h ctHandle, str []byte) (index, ns int) {
+	states := (*ct)[h.index:]
+	p := 0
+	n := h.n
+	for i := 0; i < n && p < len(str); {
+		e := states[i]
+		c := str[p]
+		if c >= e.L {
+			if e.L == c {
+				p++
+				if e.I != noIndex {
+					index, ns = int(e.I), p
+				}
+				if e.N != final {
+					// set to new state
+					i, states, n = 0, states[int(e.H)+n:], int(e.N)
+				} else {
+					return
+				}
+				continue
+			} else if e.N == final && c <= e.H {
+				p++
+				return int(c-e.L) + int(e.I), p
+			}
+		}
+		i++
+	}
+	return
+}
+
+// print writes the contractTrieSet t as compilable Go code to w. It returns
+// the total number of bytes written and the size of the resulting data structure in bytes.
+func print(t *colltab.ContractTrieSet, w io.Writer, name string) (n, size int, err error) {
+	update3 := func(nn, sz int, e error) {
+		n += nn
+		if err == nil {
+			err = e
+		}
+		size += sz
+	}
+	update2 := func(nn int, e error) { update3(nn, 0, e) }
+
+	update3(printArray(*t, w, name))
+	update2(fmt.Fprintf(w, "var %sContractTrieSet = ", name))
+	update3(printStruct(*t, w, name))
+	update2(fmt.Fprintln(w))
+	return
+}
+
+func printArray(ct colltab.ContractTrieSet, w io.Writer, name string) (n, size int, err error) {
+	p := func(f string, a ...interface{}) {
+		nn, e := fmt.Fprintf(w, f, a...)
+		n += nn
+		if err == nil {
+			err = e
+		}
+	}
+	size = len(ct) * 4
+	p("// %sCTEntries: %d entries, %d bytes\n", name, len(ct), size)
+	p("var %sCTEntries = [%d]struct{L,H,N,I uint8}{\n", name, len(ct))
+	for _, fe := range ct {
+		p("\t{0x%X, 0x%X, %d, %d},\n", fe.L, fe.H, fe.N, fe.I)
+	}
+	p("}\n")
+	return
+}
+
+func printStruct(ct colltab.ContractTrieSet, w io.Writer, name string) (n, size int, err error) {
+	n, err = fmt.Fprintf(w, "colltab.ContractTrieSet( %sCTEntries[:] )", name)
+	size = int(reflect.TypeOf(ct).Size())
+	return
+}
diff --git a/vendor/golang.org/x/text/collate/build/order.go b/vendor/golang.org/x/text/collate/build/order.go
new file mode 100644
index 0000000..2c568db
--- /dev/null
+++ b/vendor/golang.org/x/text/collate/build/order.go
@@ -0,0 +1,393 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package build
+
+import (
+	"fmt"
+	"log"
+	"sort"
+	"strings"
+	"unicode"
+
+	"golang.org/x/text/internal/colltab"
+	"golang.org/x/text/unicode/norm"
+)
+
+type logicalAnchor int
+
+const (
+	firstAnchor logicalAnchor = -1
+	noAnchor                  = 0
+	lastAnchor                = 1
+)
+
+// entry is used to keep track of a single entry in the collation element table
+// during building. Examples of entries can be found in the Default Unicode
+// Collation Element Table.
+// See http://www.unicode.org/Public/UCA/6.0.0/allkeys.txt.
+type entry struct {
+	str    string // same as string(runes)
+	runes  []rune
+	elems  []rawCE // the collation elements
+	extend string  // weights of extend to be appended to elems
+	before bool    // weights relative to next instead of previous.
+	lock   bool    // entry is used in extension and can no longer be moved.
+
+	// prev, next, and level are used to keep track of tailorings.
+	prev, next *entry
+	level      colltab.Level // next differs at this level
+	skipRemove bool          // do not unlink when removed
+
+	decompose bool // can use NFKD decomposition to generate elems
+	exclude   bool // do not include in table
+	implicit  bool // derived, is not included in the list
+	modified  bool // entry was modified in tailoring
+	logical   logicalAnchor
+
+	expansionIndex    int // used to store index into expansion table
+	contractionHandle ctHandle
+	contractionIndex  int // index into contraction elements
+}
+
+func (e *entry) String() string {
+	return fmt.Sprintf("%X (%q) -> %X (ch:%x; ci:%d, ei:%d)",
+		e.runes, e.str, e.elems, e.contractionHandle, e.contractionIndex, e.expansionIndex)
+}
+
+func (e *entry) skip() bool {
+	return e.contraction()
+}
+
+func (e *entry) expansion() bool {
+	return !e.decompose && len(e.elems) > 1
+}
+
+func (e *entry) contraction() bool {
+	return len(e.runes) > 1
+}
+
+func (e *entry) contractionStarter() bool {
+	return e.contractionHandle.n != 0
+}
+
+// nextIndexed gets the next entry that needs to be stored in the table.
+// It returns the entry and the collation level at which the next entry differs
+// from the current entry.
+// Entries that can be explicitly derived and logical reset positions are
+// examples of entries that will not be indexed.
+func (e *entry) nextIndexed() (*entry, colltab.Level) {
+	level := e.level
+	for e = e.next; e != nil && (e.exclude || len(e.elems) == 0); e = e.next {
+		if e.level < level {
+			level = e.level
+		}
+	}
+	return e, level
+}
+
+// remove unlinks entry e from the sorted chain and clears the collation
+// elements. e may not be at the front or end of the list. This should always
+// be the case, as the front and end of the list are always logical anchors,
+// which may not be removed.
+func (e *entry) remove() {
+	if e.logical != noAnchor {
+		log.Fatalf("may not remove anchor %q", e.str)
+	}
+	// TODO: need to set e.prev.level to e.level if e.level is smaller?
+	e.elems = nil
+	if !e.skipRemove {
+		if e.prev != nil {
+			e.prev.next = e.next
+		}
+		if e.next != nil {
+			e.next.prev = e.prev
+		}
+	}
+	e.skipRemove = false
+}
+
+// insertAfter inserts n after e.
+func (e *entry) insertAfter(n *entry) {
+	if e == n {
+		panic("e == anchor")
+	}
+	if e == nil {
+		panic("unexpected nil anchor")
+	}
+	n.remove()
+	n.decompose = false // redo decomposition test
+
+	n.next = e.next
+	n.prev = e
+	if e.next != nil {
+		e.next.prev = n
+	}
+	e.next = n
+}
+
+// insertBefore inserts n before e.
+func (e *entry) insertBefore(n *entry) {
+	if e == n {
+		panic("e == anchor")
+	}
+	if e == nil {
+		panic("unexpected nil anchor")
+	}
+	n.remove()
+	n.decompose = false // redo decomposition test
+
+	n.prev = e.prev
+	n.next = e
+	if e.prev != nil {
+		e.prev.next = n
+	}
+	e.prev = n
+}
+
+func (e *entry) encodeBase() (ce uint32, err error) {
+	switch {
+	case e.expansion():
+		ce, err = makeExpandIndex(e.expansionIndex)
+	default:
+		if e.decompose {
+			log.Fatal("decompose should be handled elsewhere")
+		}
+		ce, err = makeCE(e.elems[0])
+	}
+	return
+}
+
+func (e *entry) encode() (ce uint32, err error) {
+	if e.skip() {
+		log.Fatal("cannot build colElem for entry that should be skipped")
+	}
+	switch {
+	case e.decompose:
+		t1 := e.elems[0].w[2]
+		t2 := 0
+		if len(e.elems) > 1 {
+			t2 = e.elems[1].w[2]
+		}
+		ce, err = makeDecompose(t1, t2)
+	case e.contractionStarter():
+		ce, err = makeContractIndex(e.contractionHandle, e.contractionIndex)
+	default:
+		if len(e.runes) > 1 {
+			log.Fatal("colElem: contractions are handled in contraction trie")
+		}
+		ce, err = e.encodeBase()
+	}
+	return
+}
+
+// entryLess returns true if a sorts before b and false otherwise.
+func entryLess(a, b *entry) bool {
+	if res, _ := compareWeights(a.elems, b.elems); res != 0 {
+		return res == -1
+	}
+	if a.logical != noAnchor {
+		return a.logical == firstAnchor
+	}
+	if b.logical != noAnchor {
+		return b.logical == lastAnchor
+	}
+	return a.str < b.str
+}
+
+type sortedEntries []*entry
+
+func (s sortedEntries) Len() int {
+	return len(s)
+}
+
+func (s sortedEntries) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func (s sortedEntries) Less(i, j int) bool {
+	return entryLess(s[i], s[j])
+}
+
+type ordering struct {
+	id       string
+	entryMap map[string]*entry
+	ordered  []*entry
+	handle   *trieHandle
+}
+
+// insert inserts e into both entryMap and ordered.
+// Note that insert simply appends e to ordered.  To reattain a sorted
+// order, o.sort() should be called.
+func (o *ordering) insert(e *entry) {
+	if e.logical == noAnchor {
+		o.entryMap[e.str] = e
+	} else {
+		// Use key format as used in UCA rules.
+		o.entryMap[fmt.Sprintf("[%s]", e.str)] = e
+		// Also add index entry for XML format.
+		o.entryMap[fmt.Sprintf("<%s/>", strings.Replace(e.str, " ", "_", -1))] = e
+	}
+	o.ordered = append(o.ordered, e)
+}
+
+// newEntry creates a new entry for the given info and inserts it into
+// the index.
+func (o *ordering) newEntry(s string, ces []rawCE) *entry {
+	e := &entry{
+		runes: []rune(s),
+		elems: ces,
+		str:   s,
+	}
+	o.insert(e)
+	return e
+}
+
+// find looks up and returns the entry for the given string.
+// It returns nil if str is not in the index and if an implicit value
+// cannot be derived, that is, if str represents more than one rune.
+func (o *ordering) find(str string) *entry {
+	e := o.entryMap[str]
+	if e == nil {
+		r := []rune(str)
+		if len(r) == 1 {
+			const (
+				firstHangul = 0xAC00
+				lastHangul  = 0xD7A3
+			)
+			if r[0] >= firstHangul && r[0] <= lastHangul {
+				ce := []rawCE{}
+				nfd := norm.NFD.String(str)
+				for _, r := range nfd {
+					ce = append(ce, o.find(string(r)).elems...)
+				}
+				e = o.newEntry(nfd, ce)
+			} else {
+				e = o.newEntry(string(r[0]), []rawCE{
+					{w: []int{
+						implicitPrimary(r[0]),
+						defaultSecondary,
+						defaultTertiary,
+						int(r[0]),
+					},
+					},
+				})
+				e.modified = true
+			}
+			e.exclude = true // do not index implicits
+		}
+	}
+	return e
+}
+
+// makeRootOrdering returns a newly initialized ordering value and populates
+// it with a set of logical reset points that can be used as anchors.
+// The anchors first_tertiary_ignorable and __END__ will always sort at
+// the beginning and end, respectively. This means that prev and next are non-nil
+// for any indexed entry.
+func makeRootOrdering() ordering {
+	const max = unicode.MaxRune
+	o := ordering{
+		entryMap: make(map[string]*entry),
+	}
+	insert := func(typ logicalAnchor, s string, ce []int) {
+		e := &entry{
+			elems:   []rawCE{{w: ce}},
+			str:     s,
+			exclude: true,
+			logical: typ,
+		}
+		o.insert(e)
+	}
+	insert(firstAnchor, "first tertiary ignorable", []int{0, 0, 0, 0})
+	insert(lastAnchor, "last tertiary ignorable", []int{0, 0, 0, max})
+	insert(lastAnchor, "last primary ignorable", []int{0, defaultSecondary, defaultTertiary, max})
+	insert(lastAnchor, "last non ignorable", []int{maxPrimary, defaultSecondary, defaultTertiary, max})
+	insert(lastAnchor, "__END__", []int{1 << maxPrimaryBits, defaultSecondary, defaultTertiary, max})
+	return o
+}
+
+// patchForInsert eleminates entries from the list with more than one collation element.
+// The next and prev fields of the eliminated entries still point to appropriate
+// values in the newly created list.
+// It requires that sort has been called.
+func (o *ordering) patchForInsert() {
+	for i := 0; i < len(o.ordered)-1; {
+		e := o.ordered[i]
+		lev := e.level
+		n := e.next
+		for ; n != nil && len(n.elems) > 1; n = n.next {
+			if n.level < lev {
+				lev = n.level
+			}
+			n.skipRemove = true
+		}
+		for ; o.ordered[i] != n; i++ {
+			o.ordered[i].level = lev
+			o.ordered[i].next = n
+			o.ordered[i+1].prev = e
+		}
+	}
+}
+
+// clone copies all ordering of es into a new ordering value.
+func (o *ordering) clone() *ordering {
+	o.sort()
+	oo := ordering{
+		entryMap: make(map[string]*entry),
+	}
+	for _, e := range o.ordered {
+		ne := &entry{
+			runes:     e.runes,
+			elems:     e.elems,
+			str:       e.str,
+			decompose: e.decompose,
+			exclude:   e.exclude,
+			logical:   e.logical,
+		}
+		oo.insert(ne)
+	}
+	oo.sort() // link all ordering.
+	oo.patchForInsert()
+	return &oo
+}
+
+// front returns the first entry to be indexed.
+// It assumes that sort() has been called.
+func (o *ordering) front() *entry {
+	e := o.ordered[0]
+	if e.prev != nil {
+		log.Panicf("unexpected first entry: %v", e)
+	}
+	// The first entry is always a logical position, which should not be indexed.
+	e, _ = e.nextIndexed()
+	return e
+}
+
+// sort sorts all ordering based on their collation elements and initializes
+// the prev, next, and level fields accordingly.
+func (o *ordering) sort() {
+	sort.Sort(sortedEntries(o.ordered))
+	l := o.ordered
+	for i := 1; i < len(l); i++ {
+		k := i - 1
+		l[k].next = l[i]
+		_, l[k].level = compareWeights(l[k].elems, l[i].elems)
+		l[i].prev = l[k]
+	}
+}
+
+// genColElems generates a collation element array from the runes in str. This
+// assumes that all collation elements have already been added to the Builder.
+func (o *ordering) genColElems(str string) []rawCE {
+	elems := []rawCE{}
+	for _, r := range []rune(str) {
+		for _, ce := range o.find(string(r)).elems {
+			if ce.w[0] != 0 || ce.w[1] != 0 || ce.w[2] != 0 {
+				elems = append(elems, ce)
+			}
+		}
+	}
+	return elems
+}
diff --git a/vendor/golang.org/x/text/collate/build/table.go b/vendor/golang.org/x/text/collate/build/table.go
new file mode 100644
index 0000000..7eea7a6
--- /dev/null
+++ b/vendor/golang.org/x/text/collate/build/table.go
@@ -0,0 +1,81 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package build
+
+import (
+	"fmt"
+	"io"
+	"reflect"
+
+	"golang.org/x/text/internal/colltab"
+)
+
+// table is an intermediate structure that roughly resembles the table in collate.
+type table struct {
+	colltab.Table
+	trie trie
+	root *trieHandle
+}
+
+// print writes the table as Go compilable code to w. It prefixes the
+// variable names with name. It returns the number of bytes written
+// and the size of the resulting table.
+func (t *table) fprint(w io.Writer, name string) (n, size int, err error) {
+	update := func(nn, sz int, e error) {
+		n += nn
+		if err == nil {
+			err = e
+		}
+		size += sz
+	}
+	// Write arrays needed for the structure.
+	update(printColElems(w, t.ExpandElem, name+"ExpandElem"))
+	update(printColElems(w, t.ContractElem, name+"ContractElem"))
+	update(t.trie.printArrays(w, name))
+	update(printArray(t.ContractTries, w, name))
+
+	nn, e := fmt.Fprintf(w, "// Total size of %sTable is %d bytes\n", name, size)
+	update(nn, 0, e)
+	return
+}
+
+func (t *table) fprintIndex(w io.Writer, h *trieHandle, id string) (n int, err error) {
+	p := func(f string, a ...interface{}) {
+		nn, e := fmt.Fprintf(w, f, a...)
+		n += nn
+		if err == nil {
+			err = e
+		}
+	}
+	p("\t{ // %s\n", id)
+	p("\t\tlookupOffset: 0x%x,\n", h.lookupStart)
+	p("\t\tvaluesOffset: 0x%x,\n", h.valueStart)
+	p("\t},\n")
+	return
+}
+
+func printColElems(w io.Writer, a []uint32, name string) (n, sz int, err error) {
+	p := func(f string, a ...interface{}) {
+		nn, e := fmt.Fprintf(w, f, a...)
+		n += nn
+		if err == nil {
+			err = e
+		}
+	}
+	sz = len(a) * int(reflect.TypeOf(uint32(0)).Size())
+	p("// %s: %d entries, %d bytes\n", name, len(a), sz)
+	p("var %s = [%d]uint32 {", name, len(a))
+	for i, c := range a {
+		switch {
+		case i%64 == 0:
+			p("\n\t// Block %d, offset 0x%x\n", i/64, i)
+		case (i%64)%6 == 0:
+			p("\n\t")
+		}
+		p("0x%.8X, ", c)
+	}
+	p("\n}\n\n")
+	return
+}
diff --git a/vendor/golang.org/x/text/collate/build/trie.go b/vendor/golang.org/x/text/collate/build/trie.go
new file mode 100644
index 0000000..9404a34
--- /dev/null
+++ b/vendor/golang.org/x/text/collate/build/trie.go
@@ -0,0 +1,290 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The trie in this file is used to associate the first full character
+// in a UTF-8 string to a collation element.
+// All but the last byte in a UTF-8 byte sequence are
+// used to look up offsets in the index table to be used for the next byte.
+// The last byte is used to index into a table of collation elements.
+// This file contains the code for the generation of the trie.
+
+package build
+
+import (
+	"fmt"
+	"hash/fnv"
+	"io"
+	"reflect"
+)
+
+const (
+	blockSize   = 64
+	blockOffset = 2 // Subtract 2 blocks to compensate for the 0x80 added to continuation bytes.
+)
+
+type trieHandle struct {
+	lookupStart uint16 // offset in table for first byte
+	valueStart  uint16 // offset in table for first byte
+}
+
+type trie struct {
+	index  []uint16
+	values []uint32
+}
+
+// trieNode is the intermediate trie structure used for generating a trie.
+type trieNode struct {
+	index    []*trieNode
+	value    []uint32
+	b        byte
+	refValue uint16
+	refIndex uint16
+}
+
+func newNode() *trieNode {
+	return &trieNode{
+		index: make([]*trieNode, 64),
+		value: make([]uint32, 128), // root node size is 128 instead of 64
+	}
+}
+
+func (n *trieNode) isInternal() bool {
+	return n.value != nil
+}
+
+func (n *trieNode) insert(r rune, value uint32) {
+	const maskx = 0x3F // mask out two most-significant bits
+	str := string(r)
+	if len(str) == 1 {
+		n.value[str[0]] = value
+		return
+	}
+	for i := 0; i < len(str)-1; i++ {
+		b := str[i] & maskx
+		if n.index == nil {
+			n.index = make([]*trieNode, blockSize)
+		}
+		nn := n.index[b]
+		if nn == nil {
+			nn = &trieNode{}
+			nn.b = b
+			n.index[b] = nn
+		}
+		n = nn
+	}
+	if n.value == nil {
+		n.value = make([]uint32, blockSize)
+	}
+	b := str[len(str)-1] & maskx
+	n.value[b] = value
+}
+
+type trieBuilder struct {
+	t *trie
+
+	roots []*trieHandle
+
+	lookupBlocks []*trieNode
+	valueBlocks  []*trieNode
+
+	lookupBlockIdx map[uint32]*trieNode
+	valueBlockIdx  map[uint32]*trieNode
+}
+
+func newTrieBuilder() *trieBuilder {
+	index := &trieBuilder{}
+	index.lookupBlocks = make([]*trieNode, 0)
+	index.valueBlocks = make([]*trieNode, 0)
+	index.lookupBlockIdx = make(map[uint32]*trieNode)
+	index.valueBlockIdx = make(map[uint32]*trieNode)
+	// The third nil is the default null block.  The other two blocks
+	// are used to guarantee an offset of at least 3 for each block.
+	index.lookupBlocks = append(index.lookupBlocks, nil, nil, nil)
+	index.t = &trie{}
+	return index
+}
+
+func (b *trieBuilder) computeOffsets(n *trieNode) *trieNode {
+	hasher := fnv.New32()
+	if n.index != nil {
+		for i, nn := range n.index {
+			var vi, vv uint16
+			if nn != nil {
+				nn = b.computeOffsets(nn)
+				n.index[i] = nn
+				vi = nn.refIndex
+				vv = nn.refValue
+			}
+			hasher.Write([]byte{byte(vi >> 8), byte(vi)})
+			hasher.Write([]byte{byte(vv >> 8), byte(vv)})
+		}
+		h := hasher.Sum32()
+		nn, ok := b.lookupBlockIdx[h]
+		if !ok {
+			n.refIndex = uint16(len(b.lookupBlocks)) - blockOffset
+			b.lookupBlocks = append(b.lookupBlocks, n)
+			b.lookupBlockIdx[h] = n
+		} else {
+			n = nn
+		}
+	} else {
+		for _, v := range n.value {
+			hasher.Write([]byte{byte(v >> 24), byte(v >> 16), byte(v >> 8), byte(v)})
+		}
+		h := hasher.Sum32()
+		nn, ok := b.valueBlockIdx[h]
+		if !ok {
+			n.refValue = uint16(len(b.valueBlocks)) - blockOffset
+			n.refIndex = n.refValue
+			b.valueBlocks = append(b.valueBlocks, n)
+			b.valueBlockIdx[h] = n
+		} else {
+			n = nn
+		}
+	}
+	return n
+}
+
+func (b *trieBuilder) addStartValueBlock(n *trieNode) uint16 {
+	hasher := fnv.New32()
+	for _, v := range n.value[:2*blockSize] {
+		hasher.Write([]byte{byte(v >> 24), byte(v >> 16), byte(v >> 8), byte(v)})
+	}
+	h := hasher.Sum32()
+	nn, ok := b.valueBlockIdx[h]
+	if !ok {
+		n.refValue = uint16(len(b.valueBlocks))
+		n.refIndex = n.refValue
+		b.valueBlocks = append(b.valueBlocks, n)
+		// Add a dummy block to accommodate the double block size.
+		b.valueBlocks = append(b.valueBlocks, nil)
+		b.valueBlockIdx[h] = n
+	} else {
+		n = nn
+	}
+	return n.refValue
+}
+
+func genValueBlock(t *trie, n *trieNode) {
+	if n != nil {
+		for _, v := range n.value {
+			t.values = append(t.values, v)
+		}
+	}
+}
+
+func genLookupBlock(t *trie, n *trieNode) {
+	for _, nn := range n.index {
+		v := uint16(0)
+		if nn != nil {
+			if n.index != nil {
+				v = nn.refIndex
+			} else {
+				v = nn.refValue
+			}
+		}
+		t.index = append(t.index, v)
+	}
+}
+
+func (b *trieBuilder) addTrie(n *trieNode) *trieHandle {
+	h := &trieHandle{}
+	b.roots = append(b.roots, h)
+	h.valueStart = b.addStartValueBlock(n)
+	if len(b.roots) == 1 {
+		// We insert a null block after the first start value block.
+		// This ensures that continuation bytes UTF-8 sequences of length
+		// greater than 2 will automatically hit a null block if there
+		// was an undefined entry.
+		b.valueBlocks = append(b.valueBlocks, nil)
+	}
+	n = b.computeOffsets(n)
+	// Offset by one extra block as the first byte starts at 0xC0 instead of 0x80.
+	h.lookupStart = n.refIndex - 1
+	return h
+}
+
+// generate generates and returns the trie for n.
+func (b *trieBuilder) generate() (t *trie, err error) {
+	t = b.t
+	if len(b.valueBlocks) >= 1<<16 {
+		return nil, fmt.Errorf("maximum number of value blocks exceeded (%d > %d)", len(b.valueBlocks), 1<<16)
+	}
+	if len(b.lookupBlocks) >= 1<<16 {
+		return nil, fmt.Errorf("maximum number of lookup blocks exceeded (%d > %d)", len(b.lookupBlocks), 1<<16)
+	}
+	genValueBlock(t, b.valueBlocks[0])
+	genValueBlock(t, &trieNode{value: make([]uint32, 64)})
+	for i := 2; i < len(b.valueBlocks); i++ {
+		genValueBlock(t, b.valueBlocks[i])
+	}
+	n := &trieNode{index: make([]*trieNode, 64)}
+	genLookupBlock(t, n)
+	genLookupBlock(t, n)
+	genLookupBlock(t, n)
+	for i := 3; i < len(b.lookupBlocks); i++ {
+		genLookupBlock(t, b.lookupBlocks[i])
+	}
+	return b.t, nil
+}
+
+func (t *trie) printArrays(w io.Writer, name string) (n, size int, err error) {
+	p := func(f string, a ...interface{}) {
+		nn, e := fmt.Fprintf(w, f, a...)
+		n += nn
+		if err == nil {
+			err = e
+		}
+	}
+	nv := len(t.values)
+	p("// %sValues: %d entries, %d bytes\n", name, nv, nv*4)
+	p("// Block 2 is the null block.\n")
+	p("var %sValues = [%d]uint32 {", name, nv)
+	var printnewline bool
+	for i, v := range t.values {
+		if i%blockSize == 0 {
+			p("\n\t// Block %#x, offset %#x", i/blockSize, i)
+		}
+		if i%4 == 0 {
+			printnewline = true
+		}
+		if v != 0 {
+			if printnewline {
+				p("\n\t")
+				printnewline = false
+			}
+			p("%#04x:%#08x, ", i, v)
+		}
+	}
+	p("\n}\n\n")
+	ni := len(t.index)
+	p("// %sLookup: %d entries, %d bytes\n", name, ni, ni*2)
+	p("// Block 0 is the null block.\n")
+	p("var %sLookup = [%d]uint16 {", name, ni)
+	printnewline = false
+	for i, v := range t.index {
+		if i%blockSize == 0 {
+			p("\n\t// Block %#x, offset %#x", i/blockSize, i)
+		}
+		if i%8 == 0 {
+			printnewline = true
+		}
+		if v != 0 {
+			if printnewline {
+				p("\n\t")
+				printnewline = false
+			}
+			p("%#03x:%#02x, ", i, v)
+		}
+	}
+	p("\n}\n\n")
+	return n, nv*4 + ni*2, err
+}
+
+func (t *trie) printStruct(w io.Writer, handle *trieHandle, name string) (n, sz int, err error) {
+	const msg = "trie{ %sLookup[%d:], %sValues[%d:], %sLookup[:], %sValues[:]}"
+	n, err = fmt.Fprintf(w, msg, name, handle.lookupStart*blockSize, name, handle.valueStart*blockSize, name, name)
+	sz += int(reflect.TypeOf(trie{}).Size())
+	return
+}