message: Comments for PR#539
diff: #define CLASS_DIMENSION_ALIASES( Class ) \
  using Class ## 2D = Class< 2 >; \
  - using Class ## 3D = Class< 3 >;
  + using Class ## 3D = Class< 3 >
  // To avoid unused argument warning in function definition
  template< typename T > void ringmesh_unused( T const& )
  