kresd has --tls/-t by analogy with --addr/-a where the daemon opens
the socket itself.

This changeset adds equivalent functionality for inherited sockets:
--tlsfd/-T by analogy with --fd/-Sa

* daemon now processes messages over TCP stream
out-of-order and concurrently
* support for TCP_DEFER_ACCEPT
* support for TCP Fast-Open
* there are now deadlines for TCP for idle/slow
streams (to prevent slowloris; pruning)
* there is now per-request limit on timeouts
(each request is allowed 4 timeouts before bailing)
* faster request closing, unified retry/timeout timers
* rare race condition in timer closing fixed

daemon can accept existing fds on command line,
thus supporting process managers like circus or
upstart. a tiny supervisor script is attached

breathe failed to process the typedef thinking
the macro expansion was a function pointer

TODO: per-loop freelists are implemented

lists available interfaces