improve Auth0 docs example

Auth0 has an example of using capnweb in their docs: https://auth0.com/docs/quickstart/spa/capn-web.

The example does not follow the Cap'n Web auth pattern, but instead passes the auth token to every method, re-checking every time.

Also, it looks like they support only websocket in this example, not the HTTP batch protocol.

We should improve this example and send it on up to them (I'm sure they'd be happy for it to be better if possible).