diff --git a/vendor/github.com/json-iterator/go/iter.go b/vendor/github.com/json-iterator/go/iter.go
new file mode 100644
index 0000000..95ae54f
--- /dev/null
+++ b/vendor/github.com/json-iterator/go/iter.go
@@ -0,0 +1,322 @@
+package jsoniter
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+)
+
+// ValueType the type for JSON element
+type ValueType int
+
+const (
+	// InvalidValue invalid JSON element
+	InvalidValue ValueType = iota
+	// StringValue JSON element "string"
+	StringValue
+	// NumberValue JSON element 100 or 0.10
+	NumberValue
+	// NilValue JSON element null
+	NilValue
+	// BoolValue JSON element true or false
+	BoolValue
+	// ArrayValue JSON element []
+	ArrayValue
+	// ObjectValue JSON element {}
+	ObjectValue
+)
+
+var hexDigits []byte
+var valueTypes []ValueType
+
+func init() {
+	hexDigits = make([]byte, 256)
+	for i := 0; i < len(hexDigits); i++ {
+		hexDigits[i] = 255
+	}
+	for i := '0'; i <= '9'; i++ {
+		hexDigits[i] = byte(i - '0')
+	}
+	for i := 'a'; i <= 'f'; i++ {
+		hexDigits[i] = byte((i - 'a') + 10)
+	}
+	for i := 'A'; i <= 'F'; i++ {
+		hexDigits[i] = byte((i - 'A') + 10)
+	}
+	valueTypes = make([]ValueType, 256)
+	for i := 0; i < len(valueTypes); i++ {
+		valueTypes[i] = InvalidValue
+	}
+	valueTypes['"'] = StringValue
+	valueTypes['-'] = NumberValue
+	valueTypes['0'] = NumberValue
+	valueTypes['1'] = NumberValue
+	valueTypes['2'] = NumberValue
+	valueTypes['3'] = NumberValue
+	valueTypes['4'] = NumberValue
+	valueTypes['5'] = NumberValue
+	valueTypes['6'] = NumberValue
+	valueTypes['7'] = NumberValue
+	valueTypes['8'] = NumberValue
+	valueTypes['9'] = NumberValue
+	valueTypes['t'] = BoolValue
+	valueTypes['f'] = BoolValue
+	valueTypes['n'] = NilValue
+	valueTypes['['] = ArrayValue
+	valueTypes['{'] = ObjectValue
+}
+
+// Iterator is a io.Reader like object, with JSON specific read functions.
+// Error is not returned as return value, but stored as Error member on this iterator instance.
+type Iterator struct {
+	cfg              *frozenConfig
+	reader           io.Reader
+	buf              []byte
+	head             int
+	tail             int
+	captureStartedAt int
+	captured         []byte
+	Error            error
+	Attachment       interface{} // open for customized decoder
+}
+
+// NewIterator creates an empty Iterator instance
+func NewIterator(cfg API) *Iterator {
+	return &Iterator{
+		cfg:    cfg.(*frozenConfig),
+		reader: nil,
+		buf:    nil,
+		head:   0,
+		tail:   0,
+	}
+}
+
+// Parse creates an Iterator instance from io.Reader
+func Parse(cfg API, reader io.Reader, bufSize int) *Iterator {
+	return &Iterator{
+		cfg:    cfg.(*frozenConfig),
+		reader: reader,
+		buf:    make([]byte, bufSize),
+		head:   0,
+		tail:   0,
+	}
+}
+
+// ParseBytes creates an Iterator instance from byte array
+func ParseBytes(cfg API, input []byte) *Iterator {
+	return &Iterator{
+		cfg:    cfg.(*frozenConfig),
+		reader: nil,
+		buf:    input,
+		head:   0,
+		tail:   len(input),
+	}
+}
+
+// ParseString creates an Iterator instance from string
+func ParseString(cfg API, input string) *Iterator {
+	return ParseBytes(cfg, []byte(input))
+}
+
+// Pool returns a pool can provide more iterator with same configuration
+func (iter *Iterator) Pool() IteratorPool {
+	return iter.cfg
+}
+
+// Reset reuse iterator instance by specifying another reader
+func (iter *Iterator) Reset(reader io.Reader) *Iterator {
+	iter.reader = reader
+	iter.head = 0
+	iter.tail = 0
+	return iter
+}
+
+// ResetBytes reuse iterator instance by specifying another byte array as input
+func (iter *Iterator) ResetBytes(input []byte) *Iterator {
+	iter.reader = nil
+	iter.buf = input
+	iter.head = 0
+	iter.tail = len(input)
+	return iter
+}
+
+// WhatIsNext gets ValueType of relatively next json element
+func (iter *Iterator) WhatIsNext() ValueType {
+	valueType := valueTypes[iter.nextToken()]
+	iter.unreadByte()
+	return valueType
+}
+
+func (iter *Iterator) skipWhitespacesWithoutLoadMore() bool {
+	for i := iter.head; i < iter.tail; i++ {
+		c := iter.buf[i]
+		switch c {
+		case ' ', '\n', '\t', '\r':
+			continue
+		}
+		iter.head = i
+		return false
+	}
+	return true
+}
+
+func (iter *Iterator) isObjectEnd() bool {
+	c := iter.nextToken()
+	if c == ',' {
+		return false
+	}
+	if c == '}' {
+		return true
+	}
+	iter.ReportError("isObjectEnd", "object ended prematurely, unexpected char "+string([]byte{c}))
+	return true
+}
+
+func (iter *Iterator) nextToken() byte {
+	// a variation of skip whitespaces, returning the next non-whitespace token
+	for {
+		for i := iter.head; i < iter.tail; i++ {
+			c := iter.buf[i]
+			switch c {
+			case ' ', '\n', '\t', '\r':
+				continue
+			}
+			iter.head = i + 1
+			return c
+		}
+		if !iter.loadMore() {
+			return 0
+		}
+	}
+}
+
+// ReportError record a error in iterator instance with current position.
+func (iter *Iterator) ReportError(operation string, msg string) {
+	if iter.Error != nil {
+		if iter.Error != io.EOF {
+			return
+		}
+	}
+	peekStart := iter.head - 10
+	if peekStart < 0 {
+		peekStart = 0
+	}
+	peekEnd := iter.head + 10
+	if peekEnd > iter.tail {
+		peekEnd = iter.tail
+	}
+	parsing := string(iter.buf[peekStart:peekEnd])
+	contextStart := iter.head - 50
+	if contextStart < 0 {
+		contextStart = 0
+	}
+	contextEnd := iter.head + 50
+	if contextEnd > iter.tail {
+		contextEnd = iter.tail
+	}
+	context := string(iter.buf[contextStart:contextEnd])
+	iter.Error = fmt.Errorf("%s: %s, error found in #%v byte of ...|%s|..., bigger context ...|%s|...",
+		operation, msg, iter.head-peekStart, parsing, context)
+}
+
+// CurrentBuffer gets current buffer as string for debugging purpose
+func (iter *Iterator) CurrentBuffer() string {
+	peekStart := iter.head - 10
+	if peekStart < 0 {
+		peekStart = 0
+	}
+	return fmt.Sprintf("parsing #%v byte, around ...|%s|..., whole buffer ...|%s|...", iter.head,
+		string(iter.buf[peekStart:iter.head]), string(iter.buf[0:iter.tail]))
+}
+
+func (iter *Iterator) readByte() (ret byte) {
+	if iter.head == iter.tail {
+		if iter.loadMore() {
+			ret = iter.buf[iter.head]
+			iter.head++
+			return ret
+		}
+		return 0
+	}
+	ret = iter.buf[iter.head]
+	iter.head++
+	return ret
+}
+
+func (iter *Iterator) loadMore() bool {
+	if iter.reader == nil {
+		if iter.Error == nil {
+			iter.head = iter.tail
+			iter.Error = io.EOF
+		}
+		return false
+	}
+	if iter.captured != nil {
+		iter.captured = append(iter.captured,
+			iter.buf[iter.captureStartedAt:iter.tail]...)
+		iter.captureStartedAt = 0
+	}
+	for {
+		n, err := iter.reader.Read(iter.buf)
+		if n == 0 {
+			if err != nil {
+				if iter.Error == nil {
+					iter.Error = err
+				}
+				return false
+			}
+		} else {
+			iter.head = 0
+			iter.tail = n
+			return true
+		}
+	}
+}
+
+func (iter *Iterator) unreadByte() {
+	if iter.Error != nil {
+		return
+	}
+	iter.head--
+	return
+}
+
+// Read read the next JSON element as generic interface{}.
+func (iter *Iterator) Read() interface{} {
+	valueType := iter.WhatIsNext()
+	switch valueType {
+	case StringValue:
+		return iter.ReadString()
+	case NumberValue:
+		if iter.cfg.configBeforeFrozen.UseNumber {
+			return json.Number(iter.readNumberAsString())
+		}
+		return iter.ReadFloat64()
+	case NilValue:
+		iter.skipFourBytes('n', 'u', 'l', 'l')
+		return nil
+	case BoolValue:
+		return iter.ReadBool()
+	case ArrayValue:
+		arr := []interface{}{}
+		iter.ReadArrayCB(func(iter *Iterator) bool {
+			var elem interface{}
+			iter.ReadVal(&elem)
+			arr = append(arr, elem)
+			return true
+		})
+		return arr
+	case ObjectValue:
+		obj := map[string]interface{}{}
+		iter.ReadMapCB(func(Iter *Iterator, field string) bool {
+			var elem interface{}
+			iter.ReadVal(&elem)
+			obj[field] = elem
+			return true
+		})
+		return obj
+	default:
+		iter.ReportError("Read", fmt.Sprintf("unexpected value type: %v", valueType))
+		return nil
+	}
+}