sf1xx: move to PX4Rangerfinder and cleanup
sf1xx: move to PX4Rangerfinder and cleanup

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