message: Adding 64 nodes hexahedron support
diff: @@ -1045,9 +1045,10 @@ void Mesh::ReadGmshMesh(std::istream &input, int &curved, int &read_gf)
  -1,-1,-1,-1,-1, /* unsupported quadrilateral types */
  -1,-1,-1,-1,-1, /* unsupported trianglular types */
  -1,-1,-1,-1,-1, /* unsupported quadrilateral types */
  - -1,-1,-1,-1,-1,-1 /* unsupported linear types */
  - -1,-1,-1 /* unsupported types */
  + -1,-1,-1,-1,-1,-1, /* unsupported linear types */
  + -1,-1,-1, /* unsupported types */
  -1,-1,-1,-1,-1, /* unsupported tetrahedral types */
  + -1,-1,-1, /* undefined types */
  -1,-1,-1,-1,-1, /* unsupported tetrahedral types */
  -1,-1,-1,-1,-1,-1,-1,-1, /* unsupported types */
  64 /* 64-node third order hexahedron (8 nodes associated with the
  @@ -1090,7 +1091,15 @@ void Mesh::ReadGmshMesh(std::istream &input, int &curved, int &read_gf)
  10,21,12,22,26,23,15,24,14,
  4,16,5,17,25,18,7,19,6
  };
  - int hex64[] {};
  + int hex64[] {0,8,9,1,10,32,35,14, // 3rd order hexahedron
  + 11,33,34,15,3,19,18,2,
  + 12,36,37,16,40,56,57,44,
  + 43,59,58,45,22,49,48,20,
  + 13,39,38,17,41,60,61,47,
  + 42,63,62,46,23,50,51,21,
  + 4,24,25,5,26,52,53,28,
  + 27,55,54,29,7,31,30,6
  + };
  vector<Element*> elements_0D, elements_1D, elements_2D, elements_3D;
  elements_0D.reserve(num_of_all_elements);
  