generalized the insertion of the momemt order in statepoint.py
generalized the insertion of the momemt order in statepoint.py

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