Upgrade gin-gonic to latest master, fix compatibility issues

vendor/github.com/gin-gonic/gin/binding/msgpack.go

@@ -0,0 +1,28 @@
+// Copyright 2017 Manu Martinez-Almeida.  All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package binding
+
+import (
+	"net/http"
+
+	"github.com/ugorji/go/codec"
+)
+
+type msgpackBinding struct{}
+
+func (msgpackBinding) Name() string {
+	return "msgpack"
+}
+
+func (msgpackBinding) Bind(req *http.Request, obj interface{}) error {
+
+	if err := codec.NewDecoder(req.Body, new(codec.MsgpackHandle)).Decode(&obj); err != nil {
+		//var decoder *codec.Decoder = codec.NewDecoder(req.Body, &codec.MsgpackHandle)
+		//if err := decoder.Decode(&obj); err != nil {
+		return err
+	}
+	return validate(obj)
+
+}