Fix whitespace

This involves two whitespace only changes:

- Trim all trailing whitespaces
- Add final newlines that are missing from some JS files

You can confirm that this is a whitespace-only change by doing `git diff -w master` and verifying that no changes are shown.  Adding [?w=1](https://github.com/emberjs/ember.js/pull/5199/files?w=1) to the files changed URL also demonstrates this.