Update: I did a few tests and found two things we should fix:
1) You can load meshes with 0 elements. It works fine in MeshLib (it don't think it should) but it completely messes with VTK. I will do some changes so meshes will have to have at least one element. We should not need to check this when creating the sfc-object.
2) Upon mesh to geo conversion it _can_ happen that double points need to be removed. This means that the source mesh can have "double nodes". I thought this was already checked on mesh loading? We should talk about this as it shouldn't happen.