[Dune-devel] Interface class for EntitySeed

[Oliver Sander]

Dear Dune,
you may have noticed that I have added an EntitySeed interface class
to dune-grid.  We use the wrapper/engine concept for almost everything
we do in the grid interface, but it was missing for EntitySeed.
This change should go unnoticed for users of the grid interface.
However, grid implementations may need small changes.  I have done
them for all grids in dune-grid.  All tests pass here -- apologies if I 
broke anything.
One exception has been the ALUGrid implementation.  There,
the changes appeared to be a little more invasive, and I didn't dare to
mess with that.  Since ALUGrid doesn't use the official GridTraits class
anyway (which forces the use of the interface class), it still returns 
its EntitySeed
implementation class directly.
best,
Oliver