Undo layouts in emacs

Once you're used to being able to undo and redo window layouts in your windowmanager (hello ratpoison!), You feel the need to have this same feature everywhere.

;;; winner-mode
(winner-mode 1)
(global-set-key (kbd "C-x 4 u") 'winner-undo)
(global-set-key (kbd "C-x 4 r") 'winner-redo)