Fixed player punching system, please observe:

Test cases:
Punch enemy 3 times. He should now be stunned. Punch him now to do a final punch of a flashy animation that knocks him down.
Punch enemy 3 times and stun him, but this time walk into him. He should now be grabbed.
Punch enemy 3 times, then do nothing. After he is idle, punch him again, which should come out as a normal punch again.