message: take benj comments into account
diff: namespace {
  - void save_header( const GeoModel& M, std::ostream& out )
  + void save_header( const GeoModel& geomodel, std::ostream& out )
  {
  - out << "solid " << M.name() << std::endl;
  + out << "solid " << geomodel.name() << std::endl;
  }
  - void save_footer( const GeoModel& M, std::ostream& out )
  + void save_footer( const GeoModel& geomodel, std::ostream& out )
  {
  - out << "endsolid" << M.name() << std::endl;
  + out << "endsolid" << geomodel.name() << std::endl;
  }
  - void save_normal( const GeoModel& M, index_t triangle_id, std::ostream& out )
  + void save_normal(
  + const GeoModel& geomodel,
  + index_t triangle_id,
  + std::ostream& out )
  {
  - out << "facet normal " << M.mesh.facets.normal( triangle_id ) << std::endl;
  + out << "facet normal " << geomodel.mesh.facets.normal( triangle_id )
  + << std::endl;
  }
  void begin_triangle( std::ostream& out )
  @@ -61,22 +65,26 @@ namespace {
  }
  void save_triangle_vertex(
  - const GeoModel& M,
  + const GeoModel& geomodel,
  index_t triangle_id,
  index_t local_vertex_id,
  std::ostream& out )
  {
  out << "vertex "
  - << M.mesh.vertices.vertex(
  - M.mesh.facets.vertex( triangle_id, local_vertex_id ) ) << std::endl;
  + << geomodel.mesh.vertices.vertex(
  + geomodel.mesh.facets.vertex( triangle_id, local_vertex_id ) )
  + << std::endl;
  }
  - void save_triangle( const GeoModel& M, index_t triangle_id, std::ostream& out )
  + void save_triangle(
  + const GeoModel& geomodel,
  + index_t triangle_id,
  + std::ostream& out )
  {
  - save_normal( M, triangle_id, out );
  + save_normal( geomodel, triangle_id, out );
  begin_triangle( out );
  for( index_t vertex = 0; vertex < 3; vertex++ ) {
  - save_triangle_vertex( M, triangle_id, vertex, out );
  + save_triangle_vertex( geomodel, triangle_id, vertex, out );
  }
  end_triangle( out );
  }
  @@ -89,9 +97,9 @@ namespace {
  }
  }
  - void check_stl_validity( const GeoModel& M )
  + void check_stl_validity( const GeoModel& geomodel )
  {
  - if( M.mesh.facets.nb() != M.mesh.facets.nb_triangle() ) {
  + if( geomodel.mesh.facets.nb() != geomodel.mesh.facets.nb_triangle() ) {
  throw RINGMeshException( "I/O",
  "Geological model save in STL format support only triangles" );
  }
  @@ -110,13 +118,13 @@ namespace {
  */
  class STLIOHandler final: public GeoModelIOHandler {
  public:
  - virtual bool load( const std::string& filename, GeoModel& geomodel ) override
  + virtual bool load( const std::string& filename, GeoModel& geomodel ) final
  {
  throw RINGMeshException( "I/O",
  "Geological model loading of a from STL mesh not yet implemented" );
  }
  - virtual void save( const GeoModel& geomodel, const std::string& filename ) override
  + virtual void save( const GeoModel& geomodel, const std::string& filename ) final
  {
  check_stl_validity( geomodel );
  std::ofstream out( filename.c_str() );
  