Enable 'container-renderables' from Canary Ember

- Dasherized helpers/components are now looked up on the container
- Added helper_test to demonstrate how this works in EAK

Note: the bower.json solution is notably unlovely in that it's
pinned to a specific date of Canary, but that was the only way
to get the recent code in a manner that the bower.json's
`resolutions` hash could be used to resolve the conflict
b/w Canary Ember and the `ember-data-shim`'s specified Ember
dependency.