Blender Git Loki

Better fix for #32837: DDS compressed textures now no longer need to be flipped
when saving, rather we flip the compressed texture during load. The code used
here comes from the chromium O3D project:
http://src.chromium.org/chrome/trunk/o3d/core/cross/bitmap_dds.cc

Also made it only load compressed for power-of-two resolution images, it doesn't
seem to work for other resolutions, just falls back to non-compressed then.