Revision 902

The problem editor will now edit existing problems in place.  You invoke it with

http://webwork3.math.rochester.edu:1102/webwork/mth143/instructor/pgProblemEditor/0/2/
and it will edit problem 2 in set 0.

It can't edit files directly or create new files.

The problems are CHANGED!!! there is no editing in a temporary file-- the problems
are changed at every step.  BEWARE

--Mike