Part 12 - assembling the pieces together into "game"

The final stretch including:

Refactoring code to put some repeating things into sub-routines.

End of level logic with stars-animation over Santa's bag while adding
level-bonus to score.

Logic and init of state when player gets killed, finishes level or
starts a new game (in other words does lose last life), 50k score bonus
life (it's there, you will have to believe me).

Snowballs launching, mostly random with increasing difficulty for each
level (probably unhuman around level 8, hopefully completely impossible
to pass to level 99, as the game is not ready for level 100).

Tiny gameplay changes (making again possible to jump at top of the
ladder and making the player collision radius even one pixel less).