Remove: graphics/k3dsurf OR help to update to MathMod

Qt3 K3DSurf is dead upstream and was replaced by MathMod:

https://github.com/parisolab/mathmod
https://sourceforge.net/projects/k3dsurf/

Doas anyone want to port MathMod, otherwise I would suggest to remove
x11/k3dsurf?

OK to remove or does anyone volunteer?

Rafael