* python/demo/*.py load.py extracted from test.py. Added explore.py

  * python/demo/*.py load.py extracted from test.py. Added explore.py
        that only displays required tags and testAll.py that parses all
        the files of the testsuite without using unittest.
      * python/testSuite.py other additional test on new files added.
      * Data/* new test files added accordingly to the testSuite.
      * src/gdcmHeader.cxx avoid overwriting of the dictionary when
        the vr in the file differs from the one of the dictionary. --- Frog