forward-declare struct sshbuf so consumers don't need to include sshbuf.h
mention '%%' escape sequence in HostName directives and how it may
be used to specify IPv6 link-local addresses
document that -g will only work in the multiplexed case if applied to
the mux master
rework some fflush text, as requested
From: Edward
tweaks
From: Tim van der Molen