https://github.com/AFNetworking/AFNetworking
https://github.com/jessesquires/JSQMessagesViewController
https://github.com/jessesquires/JSQSystemSoundPlayer
https://github.com/relatedcode/ProgressHUD
https://github.com/relatedcode/RealtimeChat
https://github.com/relatedcode/NotificationChat
原文：http://www.cnblogs.com/boymaster/p/4368849.html