sf1xx: use new protocol for LW20/c
sf1xx: use new protocol for LW20/c

benefits:
- read & validate product name
- sensor configuration with the output we want (raw distance data)
- get signal quality

Protocol description: http://support.lightware.co.za/sf20/#/commands

Other Lightware sensors can easily be moved over to that as well.

krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,acfloria/Firmware,PX4/Firmware,acfloria/Firmware,PX4/Firmware,acfloria/Firmware,PX4/Firmware,acfloria/Firmware,krbeverx/Firmware,acfloria/Firmware,acfloria/Firmware,krbeverx/Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,acfloria/Firmware,PX4/Firmware,krbeverx/Firmware