Easing the process of upgrading the config file.

[vertiginous]

Poor design choices in the beginning of the project cause me to have to modify the pik config file when pik is upgraded. We need a better way to manage that between upgrades.

One suggestion was to add some sort of revision number to the configfile, so that pik could check for that and update it automatically when needed.

Another concern of mine is that, if an error isn't handled properly, the config file can get deleted. I think it may be wise to back up the config file somehow. One idea is to copy the config file to a ~/.pik/config.bak dir, and append a timestamp to the end.