prepare for updates xdmf3
prepare for updates xdmf3

rather than use a version of xdmf3 where cmake has been
tailored for VTK, use stock xdmf3 (which was changed to allow this)
and tell it how we want to build it

keithroe/vtkoptix,keithroe/vtkoptix,keithroe/vtkoptix,SimVascular/VTK,keithroe/vtkoptix,keithroe/vtkoptix,SimVascular/VTK,keithroe/vtkoptix,SimVascular/VTK,SimVascular/VTK,SimVascular/VTK,SimVascular/VTK,SimVascular/VTK,keithroe/vtkoptix,SimVascular/VTK,keithroe/vtkoptix