Todo
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+H: high priority
L: low priority
+[H] Frame ratio code has been changed and so the animation may need tuning.
+ Somebody do some testing and change the definitions regarding this.
+[M] When aborting a level, lives and score should remain the same as they
+ were before. Solution: make more dependency between the game engine and worldmap
+ or just backup those variables before starting a level.
[L] change lispreader to throw exceptions instead of simply assert() on
syntax error
[L] tux sometimes makes short jumps in the endsequence, mostly when