Convert to Swift 3

[dvntucker]

It'd be awfully nice if the codebase was Swift 3 instead of ObjC :D

The current plan is to get release 1.2 out, with notification and hotkeys -- probably the most in demand outstanding features -- and then go into code freeze and release the swift version as 2.0.

I already have some work done on this, but it's definitely going slower than I had anticipated. Most of the hurdles have been cleared now though and it's going smoother.

https://github.com/dvntucker/tomighty-osx/tree/swift3_conversion2