New objects (guided missile etc)

[Eero Tamminen]

Hi,

I just added following objects to Airsrike CVS:
- hippo (level 2)
- asteroid (level 3)
- ufo (comes from level 4 bonus)
- missile (comes from ufo)
- hangar (on level 6)

I re-organized the bonuses a bit so one needs to make & install
the POV stuff after building sources and before trying this stuff.


Problems:
- hippo triggers a bug in Airstrike which manifests in collision checking
  immediately after level 2 starts
- ufo doesn't rotate & balance as it should
- missile doesn't have all the fancy guidance & rotation stuff
  from Ulf's "wide-screen" Airstrike test version

I'm leaving the fixing of these upto Ulf. :-)


Next I'm going to look into adding bonus configuration option
into level files, so that we can have a bonus machine on each
level which spits out just the specified bonuses.


	- Eero