Photo Kit 框架

http://geek.csdn.net/news/detail/56031

http://www.jianshu.com/p/9988303b2429

http://blog.sina.com.cn/s/blog_acc991e50102w7zq.html

http://www.jianshu.com/p/3c59844df301/comments/935095

https://segmentfault.com/q/1010000005636505