Upgrade to Go1.6, use vendor

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

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

@@ -0,0 +1,63 @@
+// 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 (
+	"fmt"
+	"os"
+)
+
+const GIN_MODE = "GIN_MODE"
+
+const (
+	DebugMode   string = "debug"
+	ReleaseMode string = "release"
+	TestMode    string = "test"
+)
+const (
+	debugCode   = iota
+	releaseCode = iota
+	testCode    = iota
+)
+
+var gin_mode int = debugCode
+var mode_name string = DebugMode
+
+func init() {
+	value := os.Getenv(GIN_MODE)
+	if len(value) == 0 {
+		SetMode(DebugMode)
+	} else {
+		SetMode(value)
+	}
+}
+
+func SetMode(value string) {
+	switch value {
+	case DebugMode:
+		gin_mode = debugCode
+	case ReleaseMode:
+		gin_mode = releaseCode
+	case TestMode:
+		gin_mode = testCode
+	default:
+		panic("gin mode unknown: " + value)
+	}
+	mode_name = value
+}
+
+func Mode() string {
+	return mode_name
+}
+
+func IsDebugging() bool {
+	return gin_mode == debugCode
+}
+
+func debugPrint(format string, values ...interface{}) {
+	if IsDebugging() {
+		fmt.Printf("[GIN-debug] "+format, values...)
+	}
+}