UFO:Alien Invasion Code

* First set of size-reduced music tracks, more to come later...
* Some are nearly a quarter of their original size now! I can hear a slight difference myself played back-to-back with the originals, but IMO I think the quality is still decent enough I doubt most common people would notice much difference.
* I actually encoded these at even less bit-rate then what was first proposed in the forum, the target rate is still 128 but the top limit I brought down to 160, and I think these versions still sound good enough.
* TODO: After getting the other tracks downsized, I need to re-write some of my old tracks, some of these that I contributed a long time ago I never remade, and I think they don't sound very good at all compared to my more recent works. First I will downsize the other tracks though...
* Note: A few of my old tracks - for now - I cut the volume down just a tad so they don't blast compared to the other soundtracks in the game.

* updated music track and updated license to 'Creative Commons
Attribution 3.0 Unported License'

* new airfight music track by Destructavator

* use the trunk base content

* delete the base to allow to copy the trunk one

* added David Reeves music track

* Deleted some unchanges stuff after talk with mattn.

* first van2 texture by Yoshiboy