Allow more subcams.

dvmmul -- don't use entry [3] of a 3-component point!

for performance etc. tests.

And, in partiview version, make sure to *use* o2d/d2o if provided!

structure names (?!).

Default change: no longer skip blank times!
Per-data time ranges now extend overall clock range,
don't replace it.
Reset material properties (shininess, specular, ambient)
when drawing a lighted mesh.