Bug 1013464 -- intermittent dom.player is null during video_test.js unit testing

Load video.js after html is loaded into DOM to avoid video.js reference errors during unit testing runs. Also introduced more mocks to avoid errors during loading of video.js.
Since we use TDD pattern on this unit test file, we should keep it consistent. So, please change this back to `suiteSetup(function(done) {` or to modify the file to follow BDD pattern, like: `after`, `beforeEach, `afterEach`, etc.