[bugfix][IdGrid] make compile with current master.

dune/grid/idgrid/adaptcallback.hh

dune/grid/idgrid/capabilities.hh

dune/grid/idgrid/datahandle.hh

dune/grid/idgrid/entity.hh

dune/grid/idgrid/entityseed.hh

dune/grid/idgrid/geometry.hh

dune/grid/idgrid/grid.hh

dune/grid/idgrid/gridview.hh

dune/grid/idgrid/hostgridaccess.hh

dune/grid/idgrid/idset.hh

dune/grid/idgrid/indexset.hh

dune/grid/idgrid/intersection.hh

dune/grid/idgrid/intersectioniterator.hh

dune/grid/idgrid/iterator.hh

dune/grid/idgrid/twistutility.hh

dune/grid/test/CMakeLists.txt