Upgrade to Python 3.2

Upgrade to Python 3.2

bzrlib and mercurial aren't Python 3 compatible yet (and seem unlikely
to become compatible in the near future), so if you're using them, you
should stick with an older version of update-copyright.

Note that the version of Python used by update-copyright has nothing
to do with the version of Python you use in your project.  You project
doesn't even have to use Python at all.