[vtkusers] Removing lighting from points, lines, and wireframe

[Ken Martin]

Hello Folk,

We are considering removing lighting from points, lines, and wireframe
in VTK and I wanted to get some feedback on the idea. Currently
lighting is applied to a wireframe mesh by default and this frequently
causes confusion because parts of the mesh are black (or near black)
due to lighting considerations when they expect the mesh to show up.
The same thing happens less commonly for lines and points. One
suggestion is

1) remove lighting from lines, points, and wireframes

2) remove lighting from wireframes, but leave it on for points and
lines if they have normals

3) Make it an option where the default is to not use lighting (1) but
it could be turned on

4) leave it the way it is, I like my wireframes shaded

Thanks
Ken