Handle configuration conflicts

[mwylde]

CouchDB operates on a "early bird gets the worm" principle: if two people are editing the same document at the same time, the first to commit wins. Currently there's no support for conflict resolution in the web interface. There needs to be something, because otherwise once you get a conflict you can't edit that document again without reloading the app. I'm not sure how elaborate this has to be, though, considering this is probably something that's unlikely to come up in practice.