http://blog.csdn.net/hanhailong726188/article/details/46433229
http://blog.csdn.net/ff20081528/article/details/17845753
http://blog.csdn.net/xiaanming/article/details/20934541
https://github.com/ikew0ng/SwipeBackLayout
原文：http://www.cnblogs.com/vagrant1991/p/4598887.html