Swift 2.2 to Swift 3 improvements

[rogerhu]

Gotchas:

• first named parameter requires _ in front (have to make sure IBOutlets also confirm)

• Xcode 8 requires Sierra

• Enum improvements

• Protocol-oriented programming (see WWDC talks - https://developer.apple.com/videos/play/wwdc2015/408/, https://developer.apple.com/videos/play/wwdc2015/414)

• open vs. public (https://medium.com/@ryuichi/swift-3-access-control-e8035ce8569e)

• compile-time checked selectors (Swift 2.2) - https://swift.org/blog/swift-2-2-new-features/

  • selector extensions https://medium.com/swift-programming/swift-selector-syntax-sugar-81c8a8b10df3#.r2xsag2pp

• See https://swift.org/migration-guide/