VideoSupport: Fix WindowLeaked error

Calling start and requestFocus on the video view before the video was
loaded was causing a windowleaked exception.  Waiting to start the video
till after the progress dialog was dismissed and the videoview was
prepared patched the leak.
Video: Add restart/quit dialog on video complete

Convenience dialog to make it easier for the user to restart the video
or exit the video player without having to tap back, or tap the video
and re-click play.