Now properly resets the game

Just some updates, one big bugfix and some smaller ones.

• Now properly resets the game when you die, no more getting into negative lives etc
• The footstep frequency is now mostly independent of your frame rate, we estimate that at most the footsteps will be off by 50 ms, which we feel is acceptable
• The candyman now won't let you just run past him in the maze, oh no can't have that. If you defy the candyman to such a degree as trying to run past him, he'll just kill you!
• Added credits with links on the main menu!