[PATCH 1 of 6] socketserver: backport a less sucky socketserver from python 3.5.1

[Yuya Nishihara]

On Wed, 11 May 2016 16:17:08 +0100, Jun Wu wrote:
> I think we may benefit from Python 3 stdlib. For example, the "selectors"
> module makes it easy to switch to epoll/kqueue if we want to. Do you think
> we will never use them?

I don't see much benefit to use epoll/kqueue. Our code is mostly synchronous,
fewer socket events + long synchronous operation in worker process.

> If so, I can try implement a lightweight select/poll
> based forking server.

Can you wait a week or two? I want to try if I can salvage (and fix bugs of)
the fork-per-request server from chg repository. I've written both pre-forking
and fork-per-request servers for chg.