allows most of file types with non lowercase extension
known issue: textures with non lowercase extension in loose folders are visible now, but they aren't loaded, because it leads to fopen( filename.lowercase_extension )
* fix crash with nonpthreads xmllib + multithreading + output to system console
* number of code fixes
Radiant:
misc...
* fix: clone group ent / map import / saving map as : group ents name labels at 0,0,0;
* number of code fixes