[gridoperator]
import couplingutilities.hh from dune-multidomain
[SubOrdering] Fix mapping of single DOFIndices to ContainerIndices

The previous patch only got the batch mapping right, I overlooked
the simple one-at-a-time interface.
Merge branch 'master' into feature/gridglue

Conflicts:
	dune/pdelab/ordering/subordering.hh
[gridglueoperator]
assemble complete pattern
[remoteordering]
fix implementation of mapIndex
adapt to changes in dune-grid-glue
fix warning ... don't use GenericReferenceElement
[test]
gridglue: print dofIndex and containerIndex
[test]
gridglue: only check entities along the coupling interface
[test]
gridglue: reduce accuracy of printmatrix
[gridglueoperator]
don't call volume operator for the intersections
[remoteordering]
remove debug output
[gridglueoperator]
add hack to add small matrices for all
[test]
gridglue: some cleanup