~~~~~~~~~~~~~~~~~~
* Use gobject-introspection by default, using pygtk only as a fallback. This
will require a newer gir1.2-pango-1.0 than what's in Ubuntu Oneiric
(LP: 855076) and still suffers from key presses being ignored
(LP: 849732). Unset the environment variable UBUNTU_MENUPROXY to work
around the latter bug.
* Rework the gi/pygtk imports so that only the minimum is wrapped in a
try-except.
* Use /usr/bin/env python in ! line, though this should be hard-coded to the
installed version of Python in the Debian package.
* Other code cleanup (e.g. use new-style classes via __metaclass__, remove
ancient workaround for missing `set` built-in).