fix a tree-rotation bug related to SAH cost that was causing spastic unnecessary rotations
Merge branch 'master' of https://github.com/jeske/SimpleScene
batch-optimize the BVH each frame.. instead of doing it everytime an object moves
properly apply object scale to boundingSphere in BVHNodeAdaptor
ssBVH.addObject() works.. builds equivalent BVH.
added BVH.removeObject()
Merge branch 'master' of github.com:jeske/SimpleScene into shadowmap

Conflicts:
	SimpleScene/Util/ssBVH/ssBVH_SSObject.cs