FEM: ccx writer and mesh tools, fix bug in mesh group search
FEM: ccx writer and mesh tools, fix bug in mesh group search

Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master