dxtn License GPL

dxtn License GPL
Need it by OpenGL / DirectX compress textures, at moment for mesa32
Got Alesky aka Fireball permits to add it, so long it use the patent flag.
Some part in this library can contain patent, thing in USA
This library will not be build directly, you are force to
change the patent flags in the config.rbuild file to 1
But todo so, you need check you country patent.

svn path=/branches/reactx/; revision=29562