BUGFIXING in kdtree. checked special cases, like the origin is in the
edge of 3 planes of the AABB.
But now these cases work, except of some AABB bugs. E.g. everything is a
leaf. (I write a mail to Simon about this)

FIX: intersectRayWith3DSegmentPlane now returns the normal distance (not
the absolut one like before).