Add signal handler in callback
Add signal handler in callback

mkeilman/sirepo,mkeilman/sirepo,mrakitin/sirepo,mrakitin/sirepo,radiasoft/sirepo,radiasoft/sirepo,mrakitin/sirepo,radiasoft/sirepo,mkeilman/sirepo,mrakitin/sirepo,radiasoft/sirepo,mkeilman/sirepo,radiasoft/sirepo