[BUGFIX] make application instances not use Pascal case

As per the style guide, instances should use camelCase.

_Edit_: This is my first PR. Being new to Ember I've noticed a few inconsistencies around app instances. `window.App = Ember.Application.create();` is often used, which is later `application` as an argument. I don't know if it should be 'app' or 'application' but I don't think it should be 'App'.