Handle case where user forgot to tally multiplicities or nu-scatter more gracefully
Handle case where user forgot to tally multiplicities or nu-scatter more gracefully

liangjg/openmc,paulromano/openmc,liangjg/openmc,liangjg/openmc,paulromano/openmc,walshjon/openmc,paulromano/openmc,amandalund/openmc,amandalund/openmc,shikhar413/openmc,mit-crpg/openmc,mit-crpg/openmc,walshjon/openmc,mit-crpg/openmc,walshjon/openmc,walshjon/openmc,smharper/openmc,liangjg/openmc,smharper/openmc,shikhar413/openmc,shikhar413/openmc,amandalund/openmc,smharper/openmc,smharper/openmc,paulromano/openmc,amandalund/openmc,mit-crpg/openmc,shikhar413/openmc