Bug#810254: VTK7 ... VTK8?

[A. Maitland Bottoms]

... and now there has been a VTK 8.1.0 available since December.
Since VTK6 is in such good shape, I am wondering if it would be useful
to try to have multiple VTK versions co-installable in Debian (VTK6 6.3,
VTK7 7.1.1, VTK8 8.1) or if we should head towards a Buster release with
the single latest VTK and Python3 support.

I know it's been a while since I've looked into VTK, but I have some
renewed interest and am making packages for VTK 8.1.0 for my own use.
If I can help close this bug that would be good too.

-Maitland