------------------------
* SSHClient can be asked not to use an SSH agent now, and not to search
for private keys
* added WarningPolicy option for SSHClient (warn, but allow, on unknown
server keys)
* added Channel.exit_status_ready to poll if a channel has received an
exit status yet
* new demo for reverse port forwarding
* (bug 177117) fix UTF-8 passwords
* (bug 189466) fix typo in osrandom.py
* (bug 191657) potentially fix a race at channel shutdown
* (bug 192749) document that SSHClient.connect may raise socket.error
* (bug 193779) translate EOFError into AuthException during authentication
* (bug 200416) don't create a new logger object for each channel