http://www.thinkandbuild.it/learn-to-love-auto-layout-programmatically/
autolayout 在项目中的使用
https://github.com/smileyborg/TableViewCellWithAutoLayout cell
https://github.com/smileyborg/PureLayout pureLayout
http://stackoverflow.com/questions/18746929/using-auto-layout-in-uitableview-for-dynamic-cell-layouts-variable-row-heights
masonry
http://adad184.com/2014/09/28/use-masonry-to-quick-solve-autolayout/
自动布局中的一些讲解（setNeedsUpdateConstraints，updateConstraintsIfNeeded）等
http://my.oschina.net/w11h22j33/blog/208574