karma runner and saucelabs integration

So, this is long talked-about PR introducing Karma runner with https://saucelabs.com/home integration which is going to allow us to run tests on multiple platforms and different browsers.

Integration with Karma runner (http://karma-runner.github.io/0.10/index.html) allows us to run `grunt karma:unit` to run Jasmine tests in a browser(s) of choice (we can also run `grunt test` to run both server-side and client-side tests). 

For now saucelabs is not integrated with Travis but you can run `grunt ci` to see how it feels. Currently tests are run on multiple versions of IE and 3 tests are failing on IE8 (surprise, surprise). Watch out - it takes some time to run those tests on sauce...