Merge pull request #60 from ChrisGrant/demoapp

A couple of small fixes for the JSON in the demo app.
Refactoring backbarbuttonitemrenderer to BarButtonItemRenderer
Fixing up the visual test app.
Fixing the defaults.
Separating out the back buttons styles from the normal bar button styles.
Added parsing for the backBarButtonItem and incremented the JSON version.
Merge pull request #65 from ChrisGrant/backButton

Back button