added param for multiElectronAnimation.stokesParameter
added param for multiElectronAnimation.stokesParameter

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