开始iOS 7中自动布局教程(一、二)

文章来源：

http://www.raywenderlich.com/50317/beginning-auto-layout-tutorial-in-ios-7-part-1

http://www.raywenderlich.com/50319/beginning-auto-layout-tutorial-in-ios-7-part-2

中文翻译：

http://www.cocoachina.com/industry/20131203/7462.html

http://www.cnblogs.com/zer0Black/p/3977288.html