Don't read tallies.xml when OpenMC is run in plotting mode. Closes #310 on github.
Don't read tallies.xml when OpenMC is run in plotting mode. Closes #310 on
github.

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