UFO:Alien Invasion Code

* base/textures png crush.

* crushed png files

* Recompressed all textures in base/textures/tex_buildings with Trimage image compressor and commited those files, where a filesize reduction of at least 5% (up to 95.2%) was achieved

* Large versions for tex_buildings/wall023-25

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

* Licensed a few more textures

* convert tga into png