New toys

[fowler]

I installed a new module called sweep.  It lets you make surfaces of
extrusion and rotation.  The program is in /u/gcg/ngrap/sweep and the
code is in /u/gcg/ngrap/src/bin/sweep  Let me know if it does not live
up to your wildest dreams as you churn out wine glasses, chess pieces,
thumb tacks, baby bottles, flying saucers...

Also, I installed corners, which finds edges that are sharper than a
given angle.  I also installed dihedral which finds the angles between
faces and transformer which is used to manipulate matrices.  

-Celeste