binary IO are available at
http://www.angelfire.com/country/aldev0/cpphowto/cpp_BinaryFileIO.html
-----------------------------------------------------------------------------
+* Clean up src/gdcmValEntry.[h|cxx] from VoidArea
* vtk/vtkGdcmHeader.cxx: if speed becomes a concern some changes can
be made at the cost of memory consumption (refer to header of
vtk/vtkGdcmHeader.cxx)