下拉刷新—上拉加载 开源记录
KVO
https://github.com/coderyi/YiRefresh
https://www.jianshu.com/p/21837c99100e
https://www.jianshu.com/p/ed228f8a5c3c
https://www.jianshu.com/p/74e7103aa156
https://www.jianshu.com/p/8a658d0a6654
https://github.com/jijiawei/JWRefresh/tree/master/MYJWRefresh
https://github.com/wangzhaomeng/LLRefresh
代理
https://www.jianshu.com/p/228a1098e4bc
http://blog.csdn.net/x6587305x/article/details/42640291
刷新
https://www.jianshu.com/p/8a658d0a6654
https://github.com/isaced/ISRefresh
https://github.com/liyuechun/YCRefreshControl
https://github.com/pgbo/UpRefreshControl
https://github.com/inspace-io/INSPullToRefresh
https://github.com/Elliotsomething/PulldownRefreshDemo