Updating readme to show Persistence first use

It's not explicitly shown what is returned when you first call app persistence.  This is something EVERY app will have on first run, so why not show that it's nil and not error or some other object.
Merge pull request #209 from GantMan/master

Everyone needs to know this, so I want to put it in the readme
Improve code climate score for CameraController
Merge pull request #211 from ryansobol/improve_camera_controller

Improve code climate score for CameraController