You can use `grunt watch` now!
Changes:
* Re-enable QUnit (but ignore legacy tests)
* Add a sample QUnit test
* Add ability to run QUnit via `grunt watch` or `grunt test`
* Move linting to `grunt lint` task
* Add Redux to globals in linter
Change-Id: Ie4a65a8a66773d6472b3d73257267d18027ff3c3