ENH: 1. Remove remp solution of gdcmTests.cxx+ gdcmMain directly in src director...

ENH: 1. Remove remp solution of gdcmTests.cxx+ gdcmMain directly in src director, now generated in the build dir.
2. Tests as mentionned smarter
3. Some clean up
4. Add a new method in gdcmDict that return the PubDict by name this is intersting for 3rd party lib like ITK, where we could set the institution anme / patient name...