[Dune] Extract neighbouring element opposite to a certain vertex

[Christian Engwer]

> I still think that the covered lines should be dashed to have a coherent plot but maybe that's is a matter of personal taste.

As this is not so easy to achive ... it is not just changing some
style parameters... I doubt that currently anybody has the time to
redo all the pictures. THat said I also think that nobody would object
better pictures ;-)

Christian