VTK documentation

[jlchan]

@Davknapp when the VTK functionality is mature, we should add some documentation describing how to use it.

[Davknapp]

Yes, I agree.
What exactly do you mean by mature? In my opinion we need, a VTK-Writer for all 3D elements to call it mature. A nice addition would then be to have a look at hybrid meshes but in my opinion not necessary for a mature version of the VTK-Writer

[jlchan]

I just meant when the interface is settled and not likely to change. I think we could add it after adding 3D mesh capabilities, but I don't think we need to cover every element before that (since you're probably focusing more on prisms at first).

[Davknapp]

Yes, the interface probably won't change after adding the 3D writer. I don't know if it will change again when we use it for hybrid meshes in the feature.