Better couch data for browse

Corresponds to https://github.com/npm/npm-registry-couchapp/pull/209

@zeke be forewarned - testing this PR involves the npm-registry-couchapp `npm start`, `npm run load`, `npm run copy` dance :-P

(by all means, ask for help if it's not obvious)
That's for the arguments section of browse, i.e. you can look up the most starred packages (no argument) or all the people who have starred a package (argument = that package name). There's a bug in Hapi where if you send it a `null` value, it doesn't cache the data. Setting it to `false` instead makes it work just fine.