Upgrade to Go1.6, use vendor

Also make sure we're using a more recent version of godep

vendor/github.com/gin-gonic/gin/response_writer.go

@@ -0,0 +1,100 @@
+// 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 gin
+
+import (
+	"bufio"
+	"errors"
+	"log"
+	"net"
+	"net/http"
+)
+
+const (
+	NoWritten = -1
+)
+
+type (
+	ResponseWriter interface {
+		http.ResponseWriter
+		http.Hijacker
+		http.Flusher
+		http.CloseNotifier
+
+		Status() int
+		Size() int
+		Written() bool
+		WriteHeaderNow()
+	}
+
+	responseWriter struct {
+		http.ResponseWriter
+		status int
+		size   int
+	}
+)
+
+func (w *responseWriter) reset(writer http.ResponseWriter) {
+	w.ResponseWriter = writer
+	w.status = 200
+	w.size = NoWritten
+}
+
+func (w *responseWriter) WriteHeader(code int) {
+	if code > 0 {
+		w.status = code
+		if w.Written() {
+			log.Println("[GIN] WARNING. Headers were already written!")
+		}
+	}
+}
+
+func (w *responseWriter) WriteHeaderNow() {
+	if !w.Written() {
+		w.size = 0
+		w.ResponseWriter.WriteHeader(w.status)
+	}
+}
+
+func (w *responseWriter) Write(data []byte) (n int, err error) {
+	w.WriteHeaderNow()
+	n, err = w.ResponseWriter.Write(data)
+	w.size += n
+	return
+}
+
+func (w *responseWriter) Status() int {
+	return w.status
+}
+
+func (w *responseWriter) Size() int {
+	return w.size
+}
+
+func (w *responseWriter) Written() bool {
+	return w.size != NoWritten
+}
+
+// Implements the http.Hijacker interface
+func (w *responseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	hijacker, ok := w.ResponseWriter.(http.Hijacker)
+	if !ok {
+		return nil, nil, errors.New("the ResponseWriter doesn't support the Hijacker interface")
+	}
+	return hijacker.Hijack()
+}
+
+// Implements the http.CloseNotify interface
+func (w *responseWriter) CloseNotify() <-chan bool {
+	return w.ResponseWriter.(http.CloseNotifier).CloseNotify()
+}
+
+// Implements the http.Flush interface
+func (w *responseWriter) Flush() {
+	flusher, ok := w.ResponseWriter.(http.Flusher)
+	if ok {
+		flusher.Flush()
+	}
+}