Thanks to the great work of Robert Johannson, we now have Gtk3
support using the GObject introspection Python bindings. To use,
set your backend to “Gtk3Cairo” or “Gtk3Agg”.
It seems to be working well, but it would be great to get testing on
a broader set of platforms etc.
Unfortunately, the Gtk3Agg backend will not currently work under
Python 3. For the gory details, see this:
(On Fedora, you need to install the "pygobject3" package. Can
someone report back the package name for the Debian/Ubuntu folks?)