Possible API break: Extensions + Keybindings

["Jasper St. Pierre" <jstpierre mecheye net>]

For 3.4.0, we landed a giant port of keybindings to GSettings. This
was supposed to give extensions the ability to add keybindings, but
due to a review oversight, there were problems with the proposed API.
I have a patch that I would like Florian to review that changes the
API for mutter/gnome-shell to allow extensions to add keybindings.
Whether this is an API break is up for debate - while it does change
API, due to how it was constructed the only possible users for it was
the internal gnome-shell code, and we can guarantee that we can fix
that. Unfortunately, Florian is on vacation right now, and it may be a
tight squeeze between when he gets back and when he reviews the code,
so I'm hoping that the release team can help me out here.

https://bugzilla.gnome.org/show_bug.cgi?id=673014

-- 
  Jasper