HTTP/1.1 pipelining support for the server

[yoshuawuyts]

According to the spec HTTP/1.1 must be able to handle pipelined requests on the server, even if it chooses never to initiate it or even send back pipelined responses. We should ensure we're able to handle this eventually in order to comply with the HTTP/1.1 spec. It's not a pressing issue since browsers don't pipeline requests, and most client only do so when opting in to — but we should probably get around to this eventually (:

[Diggsey]

I believe this doesn't work due to the use of a BufReader in fn decode, which results in a read past the end of the first pipelined request.

If the BufReader is removed, pipelined requests should work.