Clarify Futon/Fauxton transition

At some point Fauxton will replace Futon. There are a few questions that we should clarify before we get there:

1. what happens to resources like jquery.js and jquery.couch.js that are currently in well-known places where CouchApps depend on them?

2. there are several other tickets regarding serving a human readable HTML page on `/` if the client is clearly a browser. (so people don’t have to type the `/_utils` manually, how does that play into rolling out Fauxton?

3. cool URLs don’t change: what happens to links into Futon that no longer work in Fauxton that might be coming in from the docs and other tutorials, including people’s in-house documentation?