* src/gdcmHeader.cxx gdcmHeader::gdcmHeader now calls LoadElements(),

  * src/gdcmHeader.cxx gdcmHeader::gdcmHeader now calls LoadElements(),
        hence the user doesn't need this explicit call.
        - gdcmPython/testSuite.py, gdcmPython/demo/*.py changed accordingly
          i.e. LoadElements() call removed.
      * src/gdcmCommon.h now defines UINT32_MAX (see stdint.h).
        - src/Makefile.am declares the proper flag for g++.
      * src/gdcmElValSet.h added gdcmElValSet::GenerateFreeTagKeyInGroup
        for adding user defined new tags.
        - src/gdcmHeader.cxx gdcmHeader::NewManualElValToPubDict added.
        - src/gdcmHeader.cxx gdcmHeader::AddAndDefaultElements now
          cleanly adds some gdcm added tags (like gdcmXSize, gdcmYSize...)