New reset and center commands

[fowler]

As a step toward removing normalization, I added two commands to
transform.c:  (new-center) and (new-reset).  (new-center) is a lot
like the center button on the tools panel except for the following:
	It can be called from lisp.
	If the object is the World, it loops through all the geoms in
the World and applies itself to all of them.  
	If the object is a camera, it calls (look-encompass World
object) at the end.
	One bug - it seems to stop all the motions if the object is a
camera.
	There was some debate about whether or not it should move the
cameras to look at the object that it was centering - I think this
might cause problems.  If we have a button that calls (look
targetgeom) or (look World) that should fulfill the need to point the
camera in the right direction without doing so when the user does not
want the camera to move.

(new-reset) is like the Reset button on the panel except for the
following:
	It can be called from lisp.
	It centers everything in the World.  The Reset button did this
at one time, but had started limiting itself to centering the world
and not everything in it.  Was this a bug or a design decision?  I
noticed it reduced the number of center-everything catastrophies.
	Since it calls new-center, it calls (look-reset World) on each
camera.

I also added optional y and z components to (scale) and changed the
(look) stuff to do something at least rational if not ideal in
non-Euclidean space.  

transform.c and motion.c changed.

-Celeste