[http] HttpRequest: just a commentary
[http] HttpConnection: some general minor cleanup
[http] HttpConnection: Fixes pipelined request processing. refs #53

Pipelined requests have been ignored as they had been already
read into the local buffer and on completion of the current
request in keep-alive state, the respective function just
did watch for input activity on the socket instead of checking
if we already have something in the "pipeline".