[Update] Coins, Menus, Animations

This is a major update. I added game screens (menu, configs) and have done major reworks on the HUD. In particular, I added COINS that you now get for mastering challenges. You need to spend these for UNDOs and leaps to farer levels (you can skip many, many levels and get to more interesting levels much quicker.

NOTE 1: You can jump to previous levels without any cost. But beware, jumping forward (again) costs you coins (again)!
NOTE 2: You have to press "Go to level" to really jump to the level. Without pressing this, no level change will happen.