[vtkusers] update: vtk w/ CAVElib and clipping

[Tony Lavoie]

Just in case anyone else was following this thread, I found where my
problem is. I'm sure someone gets to say 'I told you so', too.
Yes, there's frustum culling happening. It's happening with some default
vtkCamera object getting created, though otherwise unused in my vtk/CAVE
code. I'm now tracking down a solution; hope I can get it done by early
afternoon. :)

-Tony