Emit "connection" event on server when a socket connects

[sisou]

Fixes #8

Adds server-side 'connection' event on socket connection (I hope that's obvious 😄). This also exposes the request in all event payloads, I don't know if that is required, necessary or even wanted? Might be helpful to check for custom headers in a server implementation on certain message events?

[JohanWinther]

This also exposes the request in all event payloads, I don't know if that is required, necessary or even wanted? Might be helpful to check for custom headers in a server implementation on certain message events?

I have an idea to add an options param to the Websocket server constructor in order to specify what to return in the event payload. By default it should return the current objects for compatibility.

Do you think that is a good idea?

[sisou]

Jup, I agree, will update this PR.