fix bug.

1. Added `node bin/create-user`, used to create the system user, so that
the first user authentication.
2. In `lib/routes/package.js` line 48, `pkg.update(req.body);` expect
`express.bodyParser()`. So, in `server/server.js` line 19, changes the
`app.use(express.json());` to `app.use(express.bodyParser());`
3. In [bower/registry-client](https://github.com/bower/registry-client)
`lib/register.js` line 44, `if (response.statusCode !== 201) {` expect
`status code 201`. So, in `lib/routes/package.js` line 52, changes the
`res.send({` to `res.send(201, {`.
4. README.md.