VP-244: Fixed the IE9 issue with play button overlay that it doesn't receive mouse events most of time, as well as code clean-up and jslinting.
Merge branch 'master' into VP-244
Merge remote-tracking branch 'cindyli/VP-244'

* cindyli/VP-244:
  VP-244: Fixed the IE9 issue with play button overlay that it doesn't receive mouse events most of time, as well as code clean-up and jslinting.