message: Sample runs for mixed meshes in pmesh-optimizer.
diff: // Compile with: make pmesh-optimizer
  //
  //
  -// Mixed triangle / square.
  -// mpirun -np 4 pmesh-optimizer -m ../../data/star-mixed-p2.mesh -o 4 -rs 0 -mid 2 -tid 1 -fix-bnd -qo 6 -vl 1 -nor -lc 0.25
  -// Mixed tet / cube / hex:
  -// mpirun -np 4 pmesh-optimizer -m ../../data/fichera-mixed-p2.mesh -o 4 -rs 1 -mid 303 -tid 1 -fix-bnd -qo 6 -vl 1 -nor -lc 0.25
  -//
  // Sample runs:
  // Adapted analytic shape:
  // mpirun -np 4 pmesh-optimizer -m square01.mesh -o 2 -rs 2 -mid 2 -tid 4 -ni 200 -ls 2 -li 100 -bnd -qt 1 -qo 8
  //
  // Adapted discrete size:
  // mpirun -np 4 pmesh-optimizer -m square01.mesh -o 2 -rs 2 -mid 7 -tid 5 -ni 200 -ls 2 -li 100 -bnd -qt 1 -qo 8
  -// mpirun -np 4 pmesh-optimizer -m square01.mesh -o 2 -rs 2 -mid 2 -tid 5 -ni 200 -ls 2 -li 100 -bnd -qt 1 -qo 8 -cmb 2 -nor
  +// Adapted discrete size; explicit combo of metrics; mixed tri/quad mesh:
  +// mpirun -np 4 pmesh-optimizer -m ../../data/square-mixed.mesh -o 2 -rs 2 -mid 2 -tid 5 -ni 200 -bnd -qo 6 -cmb 2 -nor
  // Adapted discrete size+aspect_ratio:
  // mpirun -np 4 pmesh-optimizer -m square01.mesh -o 2 -rs 2 -mid 7 -tid 6 -ni 100 -ls 2 -li 100 -bnd -qt 1 -qo 8
  // Adapted discrete size+orientation (requires GSLIB):
  // mpirun -np 4 pmesh-optimizer -o 3 -rs 0 -mid 1 -tid 1 -ni 100 -ls 2 -li 100 -bnd -qt 1 -qo 8 -lc 10
  // ICF combo shape + size (rings, slow convergence):
  // mpirun -np 4 pmesh-optimizer -o 3 -rs 0 -mid 1 -tid 1 -ni 1000 -ls 2 -li 100 -bnd -qt 1 -qo 8 -cmb 1
  +// Mixed tet / cube / hex mesh with limiting:
  +// mpirun -np 4 pmesh-optimizer -m ../../data/fichera-mixed-p2.mesh -o 4 -rs 1 -mid 301 -tid 1 -fix-bnd -qo 6 -vl 1 -nor -lc 0.25
  // 3D pinched sphere shape (the mesh is in the mfem/data GitHub repository):
  // * mpirun -np 4 pmesh-optimizer -m ../../../mfem_data/ball-pert.mesh -o 4 -rs 0 -mid 303 -tid 1 -ni 20 -ls 2 -li 500 -fix-bnd
  // 2D non-conforming shape and equal size:
  @@ -707,7 +705,8 @@ int main (int argc, char *argv[])
  const double init_energy = a.GetParGridFunctionEnergy(x);
  - // 16. Visualize the starting mesh and metric values.
  + // Visualize the starting mesh and metric values.
  + // Note that for combinations of metrics, this only shows the first metric.
  if (visualization)
  {
  char title[] = "Initial metric values";
  