now the if clause to get the twist and not whether the item is the same

Merge branch 'paramerge' of https://users.dune-project.org/repositories/projects/dune-alugrid into paramerge

an implementation for a levelintersectioniterator for conforming refinement, that is restricted to the macro level

Because the CommDataHandleIF exports the DataType, it is indeed possible
to check whether a type T is derived from
(*)    CommDataHandle< T, typenanme T::DataType >.
We use this information to disable the generic method loadBalance( LBWeights )
in this case.

Note: If someone passes a type U derived from a type T derived from (*),
there is no way of checking this. In this case, the wrong method will be
used, hopefully resulting in a compile time error.

Note: As a side effect, the iterator test triggers an error in the edge
iterator of a 2d grid. Here, not all entities are visited.

Merge branch 'paramerge' of http://users.dune-project.org/repositories/projects/dune-alugrid into paramerge

Merge branch 'paramerge' of https://users.dune-project.org/repositories/projects/dune-alugrid into paramerge

grids seems not to work.