1.1.0: Swift 4.2 and iOS 12

• Updated for Swift 4.2 and iOS 12 (albeit both are still in beta.)
• Quickstart project recreated in Xcode 10 (also in beta.)
• API improvements.
• Bugfixes.
• Code cleanup.
• Documentation improvements.

I'm not good at writing proper change logs yet, sorry! 😓
But you can compare between tags.