Initialize termios structure with current tty setting instead of zero
So behavior should be better defined

Signed-off-by: Stefan Wahren <info@lategoodbye.de>
Tested-by: Michael Heimpold <mhei@heimpold.de>
Set termios flags for raw mode just like cfmakeraw

Signed-off-by: Stefan Wahren <info@lategoodbye.de>
Tested-by: Michael Heimpold <mhei@heimpold.de>