http://cdn2.raywenderlich.com/wp-content/uploads/2014/06/RW-Swift-Cheatsheet-0_3.pdf
http://www.raywenderlich.com/115279/swift-2-tutorial-part-2-a-simple-ios-app
http://www.raywenderlich.com/115253/swift-2-tutorial-a-quick-start
http://neonto.com/?ref=producthunt#slice-pricing
https://www.toptal.com/ios/ios-user-interfaces-storyboards-vs-nibs-vs-custom-code