Run `grunt jshint` as part of the test step.

* Fix a couple of jshint errors while we are at it.
Introduce jshint errors to ensure travis catches them.
Revert "Introduce jshint errors to ensure travis catches them."

This reverts commit 4f9023fbf3396b1dc3d9e1db0ee299fc13e9889f.
Merge pull request #245 from mozilla/issue-193-lint-on-checkin

Run `grunt jshint` as part of the test step.