gTornado add greenify support to tornado. inspired by motor and gevent

greenify https://github.com/douban/greenify

#What gTornado can do?

1. make orm async seamless
2. make blockio async in tornado
3. adapte greenify for gTornado https://github.com/alex8224/greenify

#Tested C library

1. libmysqlclient.so
2. libmemcached.so

1. greenlet
2. pymysql
3. pymemcache

1. pymysql
2. storm
3. pymemcache