v0.7.0

• #20 Fixed Linux rendering issue
• #27 Fixed CoreGraphics ambiguity build errors
• 499e6e8 Fixed UISwitch
• 9a0a1da Fixed UIView rendering crash
• 2fe04d5 Added iOS Demo app
• fbfef7d Fixed for Swift 3.0.2 compatibility
• 2d6b3d8 Replaced SDLEventPoller with UIEventFetcher
• 7fca764 Implemented UIViewAutoresizing
• 890d280 Implemented CFRunLoop support for main thread