Re #166: remove diagonal entry ("self-edge" from SCOTCH input graph, this finally seems to work (tested with scotch 6.0.3). I'm leaving the issue open because
Re #166: remove diagonal entry ("self-edge" from SCOTCH input graph,
this finally seems to work (tested with scotch 6.0.3). I'm leaving the issue
open because

* I do not get any multi-threading inside scotch yet
* I want to experiment with the default strategies, I think
  using them would be more portable and sustainable in GHOST
  (giving the user an option to build their own strings)

RRZE-HPC/GHOST,RRZE-HPC/GHOST,RRZE-HPC/GHOST,RRZE-HPC/GHOST