Xcode 5.1 Compatibility Fixes

When I tried using your code in my Xcode project, it spat out 100+ warnings. I divided them into three categories:

* `OCUnit` is deprecated in favor of `XCTest`
* Integer truncation
* Unused functions

I resolved all three issues. I also updated the gitignore to exclude Xcode 5.1 metadata files that weren’t there in earlier versions of Xcode.