UFO:Alien Invasion Code

* base/textures png crush.

* Recompressed all textures in base/textures/tex_alienb with Trimage image compressor and commited those files, where a filesize reduction of at least 5% (up to 92.8%) was achieved

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

* Lots of work on alien base power core, new textures, etc.

* Adding crate textures and prefabs to be used in alien base (also a couple updates on .map and .mat)

* Hi-res textures for alien base WIP with new map and mat files

* GPL'd tex_buildings/window001

* convert tga into png