Swift 3 support

[Dal Rupnik]

I have a test version ready on: https://github.com/Legoless/GMStepper/tree/Swift3

But would not recommend merging into master, so can you maybe create another branch and I will submit a PR.

[Günay Mert Karadoğan]

Hi @Legoless sorry for the late reply. And thank you!

I created the branch. Will be waiting for your PR. https://github.com/gmertk/GMStepper/tree/swift3

Cheers!

[Lucas Farah]

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

Thanks 😄