(client_winch_handler): New class implementing sending of
window-change messages.
(client_tty_resource): New class.
(do_pty_continuation): Hook in window-change handler, and a
resource for resetting the tty attributes when the channel is
closed.
(make_pty_request): Take a struct interact argument, rather than a
tty file desciptor.

Rev: src/client_pty.c:1.14
Rev: src/client_pty.h:1.5