Bugfix/postroll restarts

This fixes a bug where we had combined the conditions of player.ended() and the src unchanged, such that we were falling into an else condition which called player.load() whenever player.ended() returned true.
This is where the bug is.  Basically, if the player.ended() is true -- which will be the case on a burned-in postroll, it falls into the else below which the triggers a load() (and subsequently a play()) on some devices.  In the case of burned in ads, we never want to fall into that else condition.