Balance/Bugfixes

Changes to make the game more fair for the player, plus a couple bugfixes

1. Players get invincibility when hit and when respawning
2. Punch does not fling as hard as it did before
3. Increase range to save a character that got hit
4. Fixed a bug which gave hands much more health than they should have had (whoops)
5. Click the screen on game over to restart
6. Fixed a bug that let you bounce off of invisible hands in the top right corner of the screen
7. Fixed an oversight which caused the game to run far too fast on some web browsers