Added universe ID padding for hex lattices in #331
Added universe ID padding for hex lattices in #331

wbinventor/openmc,smharper/openmc,amandalund/openmc,wbinventor/openmc,paulromano/openmc,paulromano/openmc,samuelshaner/openmc,kellyrowland/openmc,lilulu/openmc,liangjg/openmc,wbinventor/openmc,kellyrowland/openmc,mjlong/openmc,amandalund/openmc,mjlong/openmc,liangjg/openmc,samuelshaner/openmc,shikhar413/openmc,lilulu/openmc,liangjg/openmc,amandalund/openmc,smharper/openmc,mit-crpg/openmc,bhermanmit/openmc,shikhar413/openmc,walshjon/openmc,lilulu/openmc,mit-crpg/openmc,johnnyliu27/openmc,smharper/openmc,amandalund/openmc,samuelshaner/openmc,shikhar413/openmc,mit-crpg/openmc,walshjon/openmc,samuelshaner/openmc,mit-crpg/openmc,wbinventor/openmc,bhermanmit/openmc,paulromano/openmc,smharper/openmc,paulromano/openmc,shikhar413/openmc,johnnyliu27/openmc,walshjon/openmc,liangjg/openmc,johnnyliu27/openmc,walshjon/openmc,johnnyliu27/openmc