Check client disconnect to exit for loop (api). Fixes #1983 (#2012)

Also update to latest melody upstream

vendor/github.com/olahol/melody/doc.go

@@ -0,0 +1,22 @@
+// Copyright 2015 Ola Holmström. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package melody implements a framework for dealing with WebSockets.
+//
+// Example
+//
+// A broadcasting echo server:
+//
+//  func main() {
+//  	m := melody.New()
+//  	http.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
+//  		m.HandleRequest(w, r)
+//  	})
+//  	m.HandleMessage(func(s *melody.Session, msg []byte) {
+//  		m.Broadcast(msg)
+//  	})
+//  	http.ListenAndServe(":5000", nil)
+//  }
+
+package melody