msp: add motor-pins command.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: convert altitude byte order.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: convert status byte order.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: convert servo byte order.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: convert motor byte order.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: rename rc output to struct msp_raw_rc.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: convert rc byte order.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: improved command loop.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: common send/recv checksum routine.

The send() side was misread, hence buggy. They're actually symmetric.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>
msp: add set-raw-rc command.

Signed-off-by: Daniel Stodden <daniel.stodden@gmail.com>