Urgent Bugfix + Optimizations

Bug hunting game... This time the repetition mechanism (button in the upper-right corner on level end screen in "Play all" mode) somehow screwed the level counter: Wrong order or missing diamonds/medals in the chapter end screen were the result.

Optimizations:
• For those who like some technical details: The contact distance of the 2D collision boundaries were set too high by default. The player-drawn line always sort of hovered two pixels above the ground on direct ground contact. This was not that much of a problem, but in some situations it was clearly visible.
• I also renamed some levels (mainly in chapter 9) because the old names felt just too boring and/or awkward. There was much more potential. Maybe I was a bit sloppy on that chapter the first time — should have spent more time thinking about that... Lesson learned ;-)