(_saved_mode): New variable.
(_save): New function.  Arrange to call _restore via the atexit module.
(_restore): New function.
(user.__init__): Default to not modifying the termios setting.
	Call _save before changing them.
(user.close): Use _restore to restore the settings.

(__all__): New constant.
(RAW): New constant.
(CBREAK): New constant.
(COOKED): New constant.
(user): New class.
(user.__init__): New method.
(user.send): New method.
(user.close): New method.

	previous run through the loop.  It may have left parseable
	data in a buffer.

(CONT): Removed.
(BREAK): Added.
(controller.__init__): Remove the __done attribute.
(controller.loop): The default is now to continue.  Break only if
	the user explicitly breaks out of the loop.  All references to
	__done removed.
(controller.re): Remove __done accesses.
(controller.eof): Ditto.
(controller.timeout): Ditto.
(controller.cont): Method removed.
(controller.__run_expectations): Default is to continue, unless
	the callback returns BREAK.
(expect_after): A callback should return None or BREAK; not CONT.
(expect): A missing callback is treated as a callback that returns
	BREAK.

(__all__): New constant.
(controller): New name for former class impl.

(__all__): New constant.