Merge dark

Cleaner approach to https://github.com/npm/private-npm-registry-couchapp/pull/8.

I get this error, though, so probably teh `npm run dev` script should just be removed?

```
$ npm run dev

> npm-registry-couchapp@2.5.5 dev /Users/isaacs/dev/npm/npm-registry-couchapp
> node dev/run.js

Running "couchdb" ["-a","dev/couch/couch.ini"]
hey
Running "node" ["./node_modules/registry-replicate/replicate.js","--seqfile=./dev/couch/sequence"]

module.js:340
    throw err;
          ^
Error: Cannot find module '/Users/isaacs/dev/npm/npm-registry-couchapp/node_modules/registry-replicate/replicate.js'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Function.Module.runMain (module.js:497:10)
    at startup (node.js:119:16)
    at node.js:906:3
```

Review plz @bcoe @seldo 
we modified validName to handle scoped modules. I don't think this is still required, because the logic now splits the scope from the name?