Make lookupHelper container aware.

* Adds functionality to lookup components from the container (replaces ember-handlebars `resolveHelper`).
* Moves `ember-handlebars/component_lookup` to `ember-views/component_lookup` (it isn't really related to handlebars at all).
* Pass the `view` into `lookupHelper` (need it for container lookups).
* Remove `lookupHelper` from `hooks` (it is just looked up).

This is needed for the `{{unbound}}` helper, and for automatic component lookup from templates.
Ah, I didn't realize we do this today...but yes we do. So caching in the container is easy peasy, but how do we invalidate when new code is added? In ember-cli we control the loader + resolver, we could invalidate the cache when the loader becomes aware of new code.