Update broccoli-jshint to show separator between runs.
Merge pull request #597 from rjackson/update-broccoli-jshint

Update broccoli-jshint to show separator between runs.
Add `app.import` to control legacy files, remove broccoli-bower.
better implementation of defaults in `EmberApp`

Lets loader + wrapInEval also be configurable.

We plan soon to make loader configurable via the underlying filter.
Please note, the current setup still does not allow this.
Use local trees instead of hardcoded folders.
Handle styles from `app.import`.
Allow populating only parts of `trees`.

Defaults only allows single depth merges.