UFO:Alien Invasion Code

* Recompressed all textures in base/textures/tex_buildings_snow with Trimage image compressor and commited those files, where a filesize reduction of at least 5% (up to 9.3%) was achieved

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

* [TEXTURE_.MAP_RESCALE-tex_buildings_snow/concrete001-0.5-0.5]
* Rescaled all concrete001 textures on all map files and prefabs (TODO:repeat this operation in data_source)
* Replaced concrete001 and normalmap with 512x512 pixel versions (was 256x256 before)

* git-renamed concrete001.jpg to concrete001.png
* replaced concrete001.jpg with png version (downscaled eX_cretebase_01.tga Nexuiz texture)
* added concrete001_hq.png, concrete001_hq_nm.png & concrete001_nm.png (downscaled eX_cretebase_01_nm.tga Nexuiz normalmap)
* updated LICENSES