Modify `loopback.rest()` to read the configuration for
`loopback.context` from `app.get('remoting')`, which is the approach
used for all other configuration options related to the REST transport.
Make `loopback.rest` self-contained, so that authentication works
out of the box.
var app = loopback();
app.enableAuth();
app.use(loopback.rest());
Note that cookie parsing middleware is not added, users have to
explicitly configure that if they want to store access tokens
in cookies.
Modify `loopback.token` to skip token lookup when the request already
contains `accessToken` property. This is in line with other
connect-based middleware like `cookieParser` or `json`.