UFO:Alien Invasion Code

* base/textures png crush.

* crushed png files

* Recompressed all textures in base/textures/tex_terrain with Trimage image compressor and commited those files, where a filesize reduction of at least 5% (up to 66.2%) was achieved

* fixed terrain texture resolutions

* they were scaled down in 4ecc43d387db42166cae500c21fd10b9b0e1e7c8

* replaced textures with gpled version