Fix multiple video bug.
Moved youtubeXhr to closure.
Fixing tests related to youtubeXhr variable.
Adding yt_test_timeout option on the backend.

Updating state.config to read yt test timeout from the attributes of
video div.
Removed unnecessary comments.
In-between commit.

Trying to solve last 4 Jasmine test failures.
Work in progress.
Work in progress.
If no sources, show error. Do not break.
Further tweaking of timeout code.
Make error message visible in fullscreen mode.
Fixing falling Jasmine tests.
More fixes.

Now when timeout is exceeded, and no non-YouTube sources, the YouTube
still continues to load.
Add acceptance tests for supporting Youtube failover.