slcand: add slcan_attach and UART settings
slcand: add slcan_attach and UART settings

slcand takes settings known from slcan_attach to configure CAN
interface, like open/close channel, set bitrate etc (Oliver Hartkopp).

In addition -S option sets UART's baudrate (Yegor Yefremov).

This way slcand combines three autilities in one: old slcand,
slcan_attach and stty.

Example: slcand -o -s8 -S 3000000 ttyUSB0

Signed-off-by: Yegor Yefremov <379041fa42359f10443de1f461b1b247ec449fae@googlemail.com>
Reviewed-by: Stefan Wahren <05c83f7cee1d5cf9307ce0d7ae6ccfa44e4deab5@i2se.com>
Signed-off-by: Oliver Hartkopp <06a38fb2ed1a2d0a17f4f06761ac2e5ace5a31ab@hartkopp.net>

carloop/can-utils-osx,carloop/can-utils-osx