Add more cell-grid support.
This adds an IOSS-based reader for cell-grid data. Files that end in .exdg (instead of .exo) will be read in as vtkCellGrid objects instead of vtkUnstructuredGrid objects.
Edited by David Thompson
This adds an IOSS-based reader for cell-grid data. Files that end in .exdg (instead of .exo) will be read in as vtkCellGrid objects instead of vtkUnstructuredGrid objects.