Remove fetch event

[futurechimp]

We will deal with rate-limiting later, let's just get a simple and reliable system working first with websockets, and we can add (probably optional) rate-limiting later.

Practically speaking, any packet data that hits the gateway will either be

(a) sent down the websocket to a connected client (if one exists) or
(b) persisted to disk for later retrieval (if no there is no connected client)

In the (b) case, binary data will immediately be streamed down to the client when it connects, without any fetch message being necessary.