Videomode development part 2

Did some more work on the videomode:
- Possibility to finish and advance a level.
- Crashing is now possible (with temporary *flickering* animation).
- Car accelerates and decelerates at start, finish and crash.
- Starfield moves with the level now (the angle of the starfield is still wrong and it does not loop yet.
- Added an intro which mentions the current level.

And here's the video: (level 3 is quite tricky :D )