upgrade ember-data-shim to 1.0.0.beta.4

I had some issues getting ember data to work with 1.0.0.beta.2, with exceptions when calling `this.store.find('model_name')` in the routes.

Upgrading to ember-data 1.0.0.beta.4 fixed this for me. The pull request updates the necessary files and removes  no longer current ember-data store setup.