cleaned Texture interface new C++ demo: textures slightly adjusted SAH for kd-tree slightly optimized kd-tree building -- moved termination cond. so it's tested before recursion minor sphere intersection optimization

demos/ModulePath
demos/*.png
demos/kdtree.obj
ccdemos/*.png
ccdemos/spheres_shadow
ccdemos/realtime
ccdemos/realtime_dragon
ccdemos/realtime_bunny
ccdemos/textures
models/bunny
models/happy
models/dragon
bin/*