message: Update CGSolver with user options and default values
diff: @@ -83,13 +83,14 @@ public:
  L2->Update();
  L2->Assemble();
  }
  - virtual void SetupCG()
  + virtual void SetupCG(int print_level = 0, int max_iter = 2000,
  + double rel_tol = 1e-15, double abs_tol = 0.0)
  {
  cg = new CGSolver();
  - cg->SetPrintLevel(0);
  - cg->SetMaxIter(2000);
  - cg->SetRelTol(sqrt(1e-30));
  - cg->SetAbsTol(sqrt(0.0));
  + cg->SetPrintLevel(print_level);
  + cg->SetMaxIter(max_iter);
  + cg->SetRelTol(rel_tol);
  + cg->SetAbsTol(abs_tol);
  }
  ~FieldInterpolant()
  {
  @@ -137,13 +138,14 @@ public:
  }
  using FieldInterpolant::SetupCG;
  // Setup the CG solver with an MPI communicator
  - virtual void SetupCG(MPI_Comm _comm)
  + virtual void SetupCG(MPI_Comm _comm, int print_level = 0, int max_iter = 2000,
  + double rel_tol = 1e-15, double abs_tol = 0.0)
  {
  cg = new CGSolver(_comm);
  - cg->SetPrintLevel(0);
  - cg->SetMaxIter(2000);
  - cg->SetRelTol(sqrt(1e-30));
  - cg->SetAbsTol(sqrt(0.0));
  + cg->SetPrintLevel(print_level);
  + cg->SetMaxIter(max_iter);
  + cg->SetRelTol(rel_tol);
  + cg->SetAbsTol(abs_tol);
  }
  ~ParFieldInterpolant()
  