Include jQuery to ember-dev

I wonder that ember-dev knows jQuery version contained in ember(or ember data).
* https://github.com/emberjs/ember-dev/blob/master/support/tests/index.html.erb#L64


If this patch is acceptable, I'll send next patch to remove [bundled jQuery](https://github.com/emberjs/ember.js/blob/master/lib/jquery-1.9.0.js) in ember.