Demonstrates how to create a small presented view that hovers in front of the interface like a UIAlertView.
Originally created in association with this tutorial article: http://radar.oreilly.com/2014/01/transcending-uialertview-on-ios-7.html
In iOS 8, the architecture for customizing presented view controllers changed very greatly from iOS 7, and the project was reorganized accordingly. For the earlier iOS 7 version, checkout commit 7410850.
Now updated to Swift 3 and 4.
