wait to load video module until YT API is ready
Mock YT.ready in Xmodule JS tests

and disable tests that fail for unrelated reasons
Remove references to onYouTubePlayerAPIReady and onHTML5PlayerAPIReady
Rebased. Updated Jasmine describe messages to make them more clearer.
Enabled 2 disabled Jasmine tests. Fixed them.
Remove outdated comment
Enabled 2nd disabled Jasmine test.
Merge pull request #1337 from edx/db/fix-video-requirejs

fix video module issue with require.js