Fix multiple video bug.
Adding yt_test_timeout option on the backend.

Updating state.config to read yt test timeout from the attributes of
video div.
Fix tests.
Add additional fallbacks.
Fixing falling Jasmine tests.
Add acceptance tests for supporting Youtube failover.
Add yt-test-url to fixtures.
Add Youtube failover parameters to tests.
Wrapped HTML error message in i18n.
Add additional acceptance tests.
Replace dunder method with better alternative.