message: Fix issue
  Reading GMSH mesh as input file, in the $Periodic section, we now consider that the Affine keyword and associated line are optional
diff: @@ -2019,9 +2019,15 @@ void Mesh::ReadGmshMesh(std::istream &input, int &curved, int &read_gf)
  for (int i = 0; i < num_per_ent; i++)
  {
  getline(input, buff); // Read and ignore entity dimension and tags
  - getline(input, buff); // Read and ignore affine mapping
  - // Read master/slave vertex pairs
  + getline(input, buff); // If affine mapping exist, read and ignore
  + if (!strncmp(buff.c_str(), "Affine", 6))
  + {
  input >> num_nodes;
  + }
  + else
  + {
  + num_nodes = atoi(buff.c_str());
  + }
  for (int j=0; j<num_nodes; j++)
  {
  input >> slave >> master;
  