Merge branch 'feature/environment_mpihelper' into 'master'

Return stored MPIHelper from Environment

See merge request !98

src/amdis/Environment.hpp

@@ -44,6 +44,11 @@ namespace AMDiS
         return mpiHelper_->size();
       }
 
+      Dune::MPIHelper& mpiHelper()
+      {
+        return *mpiHelper_;
+      }
+
     private:
       Dune::MPIHelper* mpiHelper_ = nullptr;
     };
@@ -71,6 +76,12 @@ namespace AMDiS
       return Mpi::instance().size();
     }
 
+    /// Return a reference to the stored \ref MPIHelper
+    static Dune::MPIHelper& mpiHelper()
+    {
+      return Mpi::instance().mpiHelper();
+    }
+
     /// Return the MPI_Comm object (or a fake communicator)
     static typename Dune::MPIHelper::MPICommunicator comm()
     {