Bump the version number to 0.6.4.
Bump the version number to 0.6.4.

Changes since 0.6.3:
- Add META_DATA and PATIENT_MATRIX information keys.
- The reader adds MetaData and PatientMatrix to pipeline information.
- New vtkDICOMAlgorithmClass passes MetaData along pipeline.
- New vtkDICOMApplyPalette class colors PALETTE COLOR images.
- Add UID dictionary, dicomdump prints meaning of standard UIDs.
- Now dicomdump prints the size of the PixelData element.

dgobbi/vtk-dicom,dgobbi/vtk-dicom,hendradarwin/vtk-dicom,hendradarwin/vtk-dicom,hendradarwin/vtk-dicom,dgobbi/vtk-dicom