一些reactiveCocoa资料：

http://www.raywenderlich.com/62699/reactivecocoa-tutorial-pt1

http://www.raywenderlich.com/62796/reactivecocoa-tutorial-pt2

http://www.raywenderlich.com/55384/ios-7-best-practices-part-1

http://www.raywenderlich.com/55384/ios-7-best-practices-part-1

http://www.raywenderlich.com/70598/reactivecocoa-tech-talk-video