Upgrade gin-gonic to latest master, fix compatibility issues

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

@@ -0,0 +1,24 @@
+// Copyright 2014 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 (
+	"encoding/xml"
+	"net/http"
+)
+
+type xmlBinding struct{}
+
+func (xmlBinding) Name() string {
+	return "xml"
+}
+
+func (xmlBinding) Bind(req *http.Request, obj interface{}) error {
+	decoder := xml.NewDecoder(req.Body)
+	if err := decoder.Decode(obj); err != nil {
+		return err
+	}
+	return validate(obj)
+}