Proposal: approve libnotify as official extenal dependency

["Sergey Udaltsov" <sergey udaltsov gmail com>]

Hi

As the release team kindly informed me, libnotify is not an officially
approved external dependency of GNOME yet. Several official packages
have is as optional dependency (namely, evo and gnome-applets - and
potentially gnome-control-center). It was already requested to add
this functionality to gtk+ - but since this functionality is already
available and successfully used by some official GNOME apps (and many
non-official ones) - why would not add it to the crowd?

Any comments are welcome,

Sergey