##父子控制器
当一个子控制器添加到父控制器上会自动调用willMoveToParentViewController:方法，同时需要子控制器调用didMoveToParentViewController:参数为父控制器
当一个子控制器从父控制器移除时，移除前调用willMoveToParentViewController:nil告诉子控制器其将要被移除，当从父控制器移除后调用removeFromParentViewController移除子控制器
https://github.com/vhf/free-programming-books
https://github.com/vsouza/awesome-ios
https://github.com/SnapKit/Masonry
https://github.com/dkhamsing/open-source-ios-apps https://github.com/ccgus/fmdb https://github.com/mutualmobile/MMDrawerController https://github.com/JumpWu/weapp-ide https://github.com/corderguo/XZ_WeChat https://github.com/robbdimitrov/RDVTabBarController https://github.com/wg689/Solve-App-Store-Review-Problem https://github.com/zhouhuanqiang/LearningIOS https://github.com/pili-engineering/PLPlayerKit https://github.com/kevinzhow/pop-handapp https://github.com/banchichen/TZImagePickerController https://github.com/iOS-Developer-Documents-Chinese/iOS-Developer-Documents-Chinese https://github.com/tangqiaoboy/iOSBlogCN https://github.com/lookingstars/meituan https://github.com/halx99/xxsocket https://github.com/907064772/runtime- https://github.com/wubianxiaoxian/SKFFPSLabel https://github.com/wo461604742/ZHlearniOS https://github.com/danielinoa/DIImageView https://github.com/mhqamx/RAC_Demo https://github.com/elasticolifan/LFTabsViewController https://github.com/wdxgtsh/DoubleDropMenuDemo https://github.com/shionIsMyName/SYAdLaunchView https://github.com/Lede-Inc/LDNetDiagnoService_IOS https://github.com/Hijin/NJBannerView https://github.com/zhengwenming/WeChat https://github.com/CoderJackyHuang/HYBHelperKit https://github.com/zhengwenming/WMPlayer https://github.com/oa414/objc-zen-book-cn https://github.com/jiulin/SDWebImageNote https://github.com/CoderJackyHuang/IOSCallJsOrJsCallIOS https://github.com/CoderJackyHuang/ClockAnimationDemo https://github.com/CoderJackyHuang/PushPopTransitionDemo https://github.com/CoderJackyHuang/CATransitionDemo