If you want a non gpl licensed version you can contact Thomas or Jens to discuss purchasing a license. The GPL was chosen for very specific purposes, just like ID software licenses their game engines under the GPL.
Developing away on one of
Multiple Macs running 10.6, 10.7, 10.8, and 10.9.
Linux, 8-core AMD, 8GB RAM, Fedora 18, nVidia 450 1GB