- basic code for fake-polygon support (called FGon in code). Disabled now

- hide flags now save correctly in mesh, to restore after going in/out
  editmode
- after an extrude, faces/edges could have wrong select flags
  (only in vertex select mode)
- new rule for addfacelist(); this now copies edges too, if an example
  is provided. That prevents a lot of awkward code, still testing if it
  goes as desired though...

source/blender/src/editmesh_lib.c

@@ -704,6 +704,8 @@ short extrudeflag_vert(short flag)
 		}
 		eve= nextve;
 	}
+	// since its vertex select mode now, it also deselects higher order
+	EM_selectmode_flush();
 
 	return 1;
 }