UFO:Alien Invasion Code

* base/textures png crush.

* Reduced filesize of the tex_alienb textures folder by compressing/optimizing the .png files with pngout

* WIP alien base with animated control chair thing

* GPL'd tex_buildings/window001

* Adjustments to tex_material/metal012 and 013

* Some new textures, still need work

* Some flat, tileable concrete and metal textures