使用gevent wsgi实现长轮询Long Polling和comet
http://xiaorui.cc/2015/06/27/%E4%BD%BF%E7%94%A8gevent-wsgi%E5%AE%9E%E7%8E%B0%E9%95%BF%E8%BF%9E%E6%8E%A5%E8%BD%AE%E8%AF%A2long-polling/
http://rfyiamcool.blog.51cto.com/
http://xiaorui.cc/
https://github.com/rfyiamcool