add flags for explicitly specifying gmax, hmax, vrange

------- Teem 1.5 cutoff ---------

6pack filtering, adapt vector stuff

change type of iv3Fill to take (int xi,int yi,int zi) instead of void
*here; one step towards supporting bricking.

test: two pervolumes with different sized volumes
test: NRWS doing its job

retest comparison of upsampling by probing and by unu resample

make the curvature direction code (scl.c) more robust
