release.py: Use the Version class instead of a separate helper function.
release.py: Use the Version class instead of a separate helper function.

* tools/dist/release.py
  (Version): loosen the regex, add a couple of helper functions.
  (split_version): Remove.
  (build_env, roll_tarballs, post_candidates, write_news, write_announcement):
    Use the Version class.
  (main): Automatically convern incoming version strings to Version objects.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion