* The creation of a testing div is specific to Rails, so that is
moved back out of setupTests();
* We've removed the `Discourse` globals from the acceptance helpers in favor of
`setApplication`/`getApplication`.
* We pass the container to setupTests because there is no
`__container__` in later Ember versions.
* `App` is now `app` because it's not a constant or class, it's an
instance of an application.
I also took the opportunity with this commit to move some test specific
stuff out of `discourse-loader` which is loaded on the front end of the
application. The test module building now happens in the `test_helper`
bundle.
