[Finishes 67046450, 67045868]: Add success condition for puzzle 8, remove buttons & blocks for levels 5-6

In the process, modified code to look more like flappy.

checkSuccess() is now used at the bottom of onTick().
checkSuccess() can call level specific functions, such as goal.successCondition()
playAudio() for 'win' vs. 'failure' now called inside onPuzzleComplete()

@Bjvanminnen please review