wsi timeout, wsi hrtimer, sequencer timeout and vh-protocol timer
all now participate on a single sorted us list.
The whole idea of polling wakes is thrown out, poll waits ignore the
timeout field and always use infinite timeouts.
Introduce a public api that can schedule its own callback from the event
loop with us resolution (usually ms is all the platform can do).
Upgrade timeouts and sequencer timeouts to also be able to use us resolution.
Introduce a prepared fakewsi in the pt, so we don't have to allocate
one on the heap when we need it.
Directly handle vh-protocol timer if LWS_MAX_SMP == 1
https://libwebsockets.org/pipermail/libwebsockets/2019-April/007937.html
thanks to Bruce Perens for noting it.
This doesn't change the intention or status of the CC0 files, they were
pure CC0 before (ie, public domain) and they are pure CC0 now. It just
gets rid of the (C) part at the top of the dedication which may be read
to be a bit contradictory since the purpose is to make it public domain.
Until now lws only parses headers it knows at build-time from its
prebuilt lexical analyzer.
This adds an on-by-default cmake option and a couple of apis
to also store and query "custom", ie, unknown-to-lws headers.
A minimal example is also provided.
At the moment it only works on h1, h2 support needs improvements
to the hpack implementation.
Since it bloats ah memory usage compared to without it if custom
headers are present, the related code and ah footprint can be
disabled with the cmake option LWS_WITH_CUSTOM_HEADERS, but it's
on by default normally. ESP32 platform disables it.
https://github.com/warmcat/libwebsockets/pull/1499
