geomview mouse functions for NeXT and SGI

[munzner]

New proposal: maybe the best way to have a single click select a
target is to have "select mode": a select icon (an arrow like almost
all 2D Mac/Next apps have) which when pressed means that clicking the
left mouse over something makes it the target. (Equivalent to
rightmouse-doubleclick currently).  Picking (as opposed to selecting)
could happen with control_leftmouse when in this mode.  (Equivalent to
rightmouse-singleclick currently). 

Almost everyone who has used a GUI will know that the arrow icon means
select. It's much less obscure than rightmouse or control keys...
Moreover, if we do allow multiple selections in the future, we still
have the shift key available in this mode.