Writing to VTK by default as it is more universal.
Writing to VTK by default as it is more universal.

walshjon/openmc,shikhar413/openmc,walshjon/openmc,liangjg/openmc,shikhar413/openmc,amandalund/openmc,paulromano/openmc,smharper/openmc,walshjon/openmc,liangjg/openmc,paulromano/openmc,amandalund/openmc,amandalund/openmc,amandalund/openmc,smharper/openmc,shikhar413/openmc,liangjg/openmc,paulromano/openmc,mit-crpg/openmc,smharper/openmc,mit-crpg/openmc,liangjg/openmc,mit-crpg/openmc,walshjon/openmc,mit-crpg/openmc,paulromano/openmc,smharper/openmc,shikhar413/openmc