- Update to version 2.4.0
* HTTP/2 server support is now mature and usable! LWS_WITH_HTTP2=1 enables it.
Uses ALPN to serve HTTP/2, HTTP/1 and ws[s] connections all from the same
listen port seamlessly. (Requires ALPN-capable OpenSSL 1.1 or mbedTLS).

* LWS_WITH_MBEDTLS=1 at CMake now builds and works against mbedTLS instead of
OpenSSL. Most things work identically, although on common targets where
OpenSSL has acceleration, mbedTLS is many times slower in operation. However
it is a lot smaller codewise.

* Generic hash apis introduced that work the same on mbedTLS or OpenSSL backend

* LWS_WITH_PEER_LIMITS tracks IPs across all vhosts and allows restrictions on
both the number of simultaneous connections and wsi in use for any single IP

* lws_ring apis provide a generic single- or multi-tail ringbuffer... mirror
protocol now uses this. Features include ring elements may be sized to fit
structs in the ringbuffer, callback when no tail any longer needs an element
and it can be deleted, and zerocopy options to write new members directly
into the ringbuffer, and use the ringbuffer element by address too.

* abstract ssh 2 server plugin included, with both plugin and standalone
demos provided. You can bind the plugin to a vhost and also serve full-
strength ssh from the vhost. IO from the ssh server is controlled by an
"ops" struct of callbacks for tx, rx, auth etc.

* Many fixes, cleanups, source refactors and other improvements.
- rebase patch:
* libwebsockets-norpmtools.patch