MSNavigationSwipeController
https://github.com/MarcoSero/MSNavigationSwipeController
简单的给Navigation添加一个手势,然后pop
ios7以及ios6下的返回
http://www.cnblogs.com/lexingyu/p/3432444.html
http://www.cnblogs.com/lexingyu/p/3434340.html
http://www.vinqon.com/codeblog/?detail/11108
https://github.com/vinqon/MultiLayerNavigation
https://github.com/aelam/CoolPop-iOS
