Use web notifications for betterifying your TDD

If your browser supports web notifications a new `Notifications`
checkbox will appear in the toolbar menu. When checked a `Fail`
notification will show when any tests have failed and a `Pass`
notification will show when all tests are green. Tomsters added for
scale.

Support for this feature is added through ember-qunit-notifications
Merge pull request #804 from bcardarella/bc-notifications

Use web notifications for betterifying your TDD