Improve vtkUniformGridAMR Selection Support
vtkExtractSelection now properly works for vtkUniformGridAMR subclasses. This was achieved by Modifying vtkDataObjectTree to support vtkUniformGridAMR for CopyStructure, GetDataSet, SetDataSet. Also when creating the hierarchy of a vtkUniformGrid, now all composite indices are in a level are included. Finally, as we prepare to deprecate vtkMultiBlockDataSet, if the input is a vtkUniformGridAMR, vtkExtractSelection now generates a vtkPartitionedDataSetCollection instead of a vtkMultiBlockDataSet.
Edited by Spiros Tsalikis