Break out rules from the rest of the settings file

[davidbo]

I have three machines on which I use Mulberry. I would like to be able to synchronize the rules between these machines without synchronizing the rest of the settings. The easiest way to accomplish this would probably be to modularize the setting file so that the user simply could rsync whatever text file (s)he is interested in keeping up to date.

There are probably other sections of the settings file where extracting into separate files also would make sense.