Migrate to Swift 5.1

[thejeff77]

Would be cool if this was updated to a newer swift version, as your tutorial is still the most succinct and helpful articles on how to do this with example code.

[chenr2]

Thanks for the kind words. I haven't worked with Swift or iOS for years, so I wouldn't know how to update this even if I wanted to. Anyone is free to take this as their own and iterate on it though.

[mdhasanshaikh]

Hi author,
Hope you are doing good.
Thank you for explaining all the things related to transitionDelegate and making the repository available to us.
Would like to migrate this source code to swift 5.1. Please add me as a collaborator. Thanks.