socket.io发送给指定的客户端

http://www.cnblogs.com/ajccom/archive/2013/07/18/3197809.html

http://stackoverflow.com/questions/10058226/send-response-to-all-clients-except-sender-socket-io

http://cnodejs.org/topic/4feb37348a7cb2d22b4edf96

https://github.com/leizongmin/qchat/blob/master/lib/room.js

http://cnodejs.org/topic/5153e2b85dff253b372ad193

http://blog.fens.me/nodejs-socketio-chat/