Fixes for hex lattice representation in #331
Fixes for hex lattice representation in #331

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