Use global index sets by the dune-parmg module

This MR contains most of the changes of !22 (closed) , with some extra cleanup.

dune/gfe/parallel/globalmapper.hh

@@ -22,25 +22,24 @@ namespace Dune {
     typedef Dune::ParMG::EntityMasterRank<typename Basis::GridView> Master;
     typedef std::vector<char> DofMaster;
 
-    GlobalMapper(const GridView& gridView_)
+    GlobalMapper(const Basis& basis)
     {
-      Basis b = gridView_;
-      DofMap dofmap = Dune::ParMG::entitiesToDofsMap(&b);
-      Master m = Dune::ParMG::entityMasterRank(gridView_, [&](int, int codim) -> bool {
+      DofMap dofmap = Dune::ParMG::entitiesToDofsMap(&basis);
+      Master m = Dune::ParMG::entityMasterRank(basis.gridView(), [&](int, int codim) -> bool {
               return dofmap.codimSet().test(codim);
             });
-      DofMaster dofmaster = Dune::ParMG::dofMaster(b, m);
+      DofMaster dofmaster = Dune::ParMG::dofMaster(basis, m);
 
-      coarseGlobalDof_ = globalDof(b,m, dofmap);
+      coarseGlobalDof_ = globalDof(basis,m, dofmap);
 
       // total number of degrees of freedom
       size_ = coarseGlobalDof_.size;
     }
 #else
-    GlobalMapper(const GridView& gridView_)
+    GlobalMapper(const Basis& basis)
     {
       // Total number of degrees of freedom
-      size_ = gridView.size();
+      size_ = basis.size();
     }
 #endif