Fixed hex_lattice negative distances to boundaries
Fixed hex_lattice negative distances to boundaries

Checked all non-CMFD tests; they all pass except score_flux_yn; need to investigate that failure closely

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