Added restriction energy constraint on sampling Watt spectrum.
Added restriction energy constraint on sampling Watt spectrum.

mit-crpg/openmc,smharper/openmc,sxds/opemmc,lilulu/openmc,mit-crpg/openmc,smharper/openmc,shikhar413/openmc,keadyk/openmc_mg_prepush,kellyrowland/openmc,mit-crpg/openmc,kellyrowland/openmc,johnnyliu27/openmc,nhorelik/openmc,shikhar413/openmc,amandalund/openmc,paulromano/openmc,mjlong/openmc,keadyk/openmc_mg_prepush,amandalund/openmc,shenqicang/openmc,johnnyliu27/openmc,shikhar413/openmc,johnnyliu27/openmc,paulromano/openmc,mjlong/openmc,shenqicang/openmc,smharper/openmc,keadyk/openmc_mg_prepush,paulromano/openmc,smharper/openmc,liangjg/openmc,amandalund/openmc,liangjg/openmc,shikhar413/openmc,walshjon/openmc,paulromano/openmc,nhorelik/openmc,samuelshaner/openmc,walshjon/openmc,wbinventor/openmc,bhermanmit/openmc,samuelshaner/openmc,sxds/opemmc,walshjon/openmc,amandalund/openmc,lilulu/openmc,bhermanmit/openmc,samuelshaner/openmc,mit-crpg/openmc,liangjg/openmc,wbinventor/openmc,liangjg/openmc,bhermanmit/cdash,lilulu/openmc,walshjon/openmc,wbinventor/openmc,samuelshaner/openmc,johnnyliu27/openmc,wbinventor/openmc