surface area measurements

[Bill Brown]

If anybody is going to use the program I sent yesterday, you
might want to change the line:
   double              xarea, sz;
to this:
   double              xarea=0.0, sz;

and if anybody's interested I also have a version that 
calculates two guesses for each triangle pair and keeps
track of a min and max estimate - email me if you want it.

- Bill