Swift 3 compatibility

[lfarah]

Hey, I'd love to see this lib available in Swift 3 so I can implement it in my project.

Thanks 😄

[coderbec]

Awesome! Doing it this weekend :-)

[coderbec]

Yo so upon commencing this I realised that the swift examples used the obj-c classes with a bridging header and converting the ViewController code to Swift 3 syntax was an incredibly simple job so I did that on a branch called swift3, which I'm about to submit as a pull request.
This seemed way too easy when I'd geared myself up for a personal challenge, so I'm gonna submit "create swift classes" as another issue. I'm assuming there's a possibility that peeps want the actual classes as swift classes, so that they can just drag them in, so I'm going to create those.