FEM: elmer tasks, better handling of not available elmer env variables
FEM: elmer tasks, better handling of not available elmer env variables

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