Merge branch 'feature/fix-fastamg-buildhierarchy' into 'master'

[bugfix] Fixes access to non-existing parallel info in FastAMG::recalculateHierachy

recalculateHierarchy() assumed that there is information avaiable
that is only there in parallel runs. This failed miserably.

This commit fixes this be implementing dummy versions for
redistributing matrices in  a sequential run and does not
query any parallel stuff any more

This closes #11.

See merge request !34