SSH channels, I noticed that I hand't ever finished the terminal
type/size "stuff", and while fixing that, I noticed that the hack
for SyncTERM was done wrong.

Fix the whole thing, and now Synchronet and SyncTERM both properly
support terminal type and size over SSH.  It also looks trivial to
support the SSH window size change message, but I'm not doing that
tonight.

Unfortunately, this is a patch on a patch, so is a bit fragile.
It should really have the patches merged at some point.