New demo

Took long enough -_-

New music, 3 levels, 3 bosses. Not finalized by any stretch of the imagination'; but enough new stuff that I think it's worth showing.

(swiped from my post on shmups)
Performance notes:

For lower spec systems (ie netbook), set fx to no blur or minimum, set debris off, music off. Medal mode might also cause a hit from the higher instance count. None of these have a *huge* impact on performance; but it's enough to help.

'No blur' gives the game a slightly sharper look, too. I think I prefer it slightly.

Random stuff/glitches/ little crap I forgot to fix:
- small medals are occasionally counted twice at the end of a stage
- if you change weapons while a powerup is moving towards you, it will keep moving
- snake segments sometimes won't die with the head section
- train sections sometimes take longer to self-destruct than they should
- Talons sometimes target enemies that can't be hit