* src/gdcmValEntry.h: member voidArea type changed from char* to void*.

* src/gdcmValEntry.h: member voidArea type changed from char* to void*.
    * src/gdcmBinEntry.h: member voidArea commented out, since it potentially
      conflicts with gdcmValEntry::voidArea.
    * src/gdcmValEntry.cxx: unmatching comment wiped out.
    * src/gdcmVR.[h|cxx]: added two predicates that partition the possible
      Value representation between StringRepresentable and BinaryRepresentable.
    * src/gdcmDocument.cxx:
      - method ParseDES: proper indentation restored and usage of
        gdcmVR::IsVROfGdcmStringRepresentable wired in.
      - method LoadDocEntry: the fingerprint left in the SetValue() of
        unloaded entries (length > MaxSizeLoadEntry) had curiously been
        removed. Reverting to previous code segment with the proper
        dynamic_cast< gdcmValEntry* >.
        Note: this was (partially) breaking the python test suite
              (gdcmPython/testSuite.py) that made usage of the above
              fingerprint to check presence of "Pixel Data".
    * src/gdcmDocEntry.h: coding style.
    * gdcmPython/__init__.py: environement variable GDCM_DATA_PATH is
      now taken into account.
    * gdcmPython/gdcm.i: adaptation to the new internal representation
      of gdcm (exit gdcmParser, hello gdcmDocument).
    * gdcmPython/testSuite.py: quick and dirty fix for loading vtkgdcmPython
      on posix.
    * gdcmPython/demo/PrintHeader.py: doesn't use the gdcmDocument::Print()
      anymore, but instead prints the loaded Python dictionary.
    * .... alas, the python testSuite is still broken.