Accels scm file - Make shortcuts appear in some kind of order

(This request may not matter if the following request is added #127 even if it does, probably would still be nice to have organized)

I noticed that the accels.scm shortcuts file that Ristretto generates is in a very random order.
If it is possible, suggesting to have this file generate in some kind of order, keeping similar items together.
Some examples would be..
-Keep next/previous image hotkeys together
-Keep all the zoom based items together
-Rotate items together
-There are four shortcuts for the Thumbnail viewer positioning "pos"

This could make it a little easier for users to be able to setup custom shortcuts.

Thank You