http://swifter.tips/
https://www.natashatherobot.com/using-swift-extensions/
http://www.swifthumb.com/article-189-1.html
http://swiftcn.io/doc/
http://blog.csdn.net/column/details/banningsswiftrelated.html
http://www.tuicool.com/articles/fMbIJv
http://www.cocoachina.com/special/swift/
http://www.cocoachina.com/cms/tags.PHP?/Swift/
