libwebsockets

sspc: ssv1: add serialization protocol versioning

Let's add a byte on the first message that sspc clients send,
indicating the version of the serialization protocol that the
client was built with.

Start the version at 1, we will add some more changes in other
patches and call v1 (now it has the versioning baked in)
the first real supported serialization version, this patch must
be applied with the next patches to actually represent v1
protocol changes.

This doesn't require user setting, the client is told what version
it supports in LWS_SSS_CLIENT_PROTOCOL_VERSION.  The proxy knows
what version(s) it can support and loudly hangs up on the client
if it doesn't understand its protocol version.