Add basic tests. Fixes #30.

I've added a small suite of basic view tests, using [FBSnapshotTestCase](https://github.com/facebook/ios-snapshot-test-case). We should now be confident that any changes made will not affect existing installs.
![screen shot 2014-05-18 at 01 18 33](https://cloud.githubusercontent.com/assets/343450/3006357/75387a7e-de22-11e3-9968-f3a100d97c3a.png)

:beers: :+1: