Create Basic App

All business logic is in ViewController.swift
It seems like [Key-Value Observing](http://nshipster.com/key-value-observing/) doesn't work quite the same way in swift as Obj-C. It might be good to use swift's built in [Property Observers](https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Properties.html#//apple_ref/doc/uid/TP40014097-CH14-XID_378) or the the [Observable Swift Library](https://github.com/slazyk/Observable-Swift) built on top of that.