[Twisted-Python] Windows spawnProcess - Child process inherits files and sockets (POSIX does not)

[exvito here]

> Thank you to, again. I will issue PRs against pywincffi such that the
> APIs are available. They most probably won't be up to pywincffi's
> standards/requirements but I expect we can cooperate under that
> context and go from there.

For completeness, if anyone wants to follow-along or contribute, first
PR is https://github.com/opalmer/pywincffi/pull/66.

Work will continue there. Once it becomes "Twisted ready" we'll bring
the discussion back here.

Thanks to all.
-- 
exvito