FEM: fluid material, fix command to add such material
FEM: fluid material, fix command to add such material

usakhelo/FreeCAD,usakhelo/FreeCAD,Fat-Zer/FreeCAD_sf_master,usakhelo/FreeCAD,Fat-Zer/FreeCAD_sf_master,usakhelo/FreeCAD,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,usakhelo/FreeCAD,usakhelo/FreeCAD,usakhelo/FreeCAD,Fat-Zer/FreeCAD_sf_master