Added node unit test runner with code coverage reporting

I added node QUnit-compatible runner [gt](https://github.com/bahmutov/gt) (my own package) that provides code coverage via istanbul. It runs under `npm test` command, runs same tests as QUnit in phantomjs instance, but tells overall coverage stats + generates detailed HTML report in cover/lcov-report/index.html.

It would be very easy to send the coverage report to [coveralls.io if needed](http://bahmutov.calepin.co/code-coverage-via-gt-and-coveralls.html)

Here is the CLI info:

![screen shot 2014-03-11 at 10 27 35 pm](https://f.cloud.github.com/assets/2212006/2393327/55b3c92e-a98e-11e3-9a6f-7391502c0f33.png)