Switched to ARC, added Xcode 5 support.

I'm gonna chalk it up to the latest DP for Xcode 5, but I found myself needing to blow away my derived data this morning… a fork, a menu command, and a few keystrokes later, and this project has been switched to ARC, and is compatible with Xcode 5.

Screenshot time!

![screenshot 2013-08-26 11 06 24](https://f.cloud.github.com/assets/58783/1027055/cea896c2-0e69-11e3-8a9f-6545412f64b7.png)

I split it up into two commits (one for the ARC switch, one for the Xcode 5 support). This should fix issue #8. Enjoy!