https://www.gitbook.com/book/numbbbbb/-the-swift-programming-language-/details
https://github.com/ipader/SwiftGuide#swift_courses
http://www.objc.io/issues/
http://www.raywenderlich.com/category/ios
https://developer.apple.com/resources/
原文：http://www.cnblogs.com/zyguo/p/4638773.html