Calculate all offsets. Makes life with ParMETIS easier.
Now testing adaption and repartitioning in 2D.
Ignore dune-ug-hpc.pc and directory 'build-cmake'

Signed-off-by: Convex Function <329364@gehry.mathepool.rwth-aachen.de>
Include the process rank as a scalar data field on the grid

This allows for easier visualization of the partition field in ParaView

Signed-off-by: Convex Function <329364@gehry.mathepool.rwth-aachen.de>
Fix a -Wreorder warning

Signed-off-by: Convex Function <329364@gehry.mathepool.rwth-aachen.de>
leafView() --> leafGridView() (the former is deprecated)

Signed-off-by: Convex Function <329364@gehry.mathepool.rwth-aachen.de>
Use proper numbering of the Interior elements

ParMetis only knows about interior elements, and numbers them accordingly.
However, the element list of a Dune grid will also contain Ghost elements,
and they may appear anywhere in the list of elements.  This patch adds
proper renumbering of the ParMetis output to the numbering produced by
a MultipleCodimMultipleGeomTypeMapper, which is the one expected by
the UGGrid loadBalance method.

Signed-off-by: Convex Function <329364@gehry.mathepool.rwth-aachen.de>