Update to pod structure.

This is to serve as an example of how the currently pending PR to the ember-jj-abrams-resolver will allow an application to be structured.

The only possibly odd part was that I actually created a subdirectory for the itemController manually. This *might* need to be addressed in Ember itself, but in the end the solution that I went with was to simply specify `itemController='todos/item-controller'` which doesn't seem TOO bad. A possible solution to this upstream would be to make itemControllers their own type, and therefor the actual path for this item controller would have been `app/todos/item-controller.js`.

Please note, this should not be merged until the resolver PR is merged and we can update `bower.json` in this PR to point to main fork again.

https://github.com/stefanpenner/ember-jj-abrams-resolver/pull/16