ArduRover 4.1.0-dev Mower w/GPS Yaw

Quick update showcasing GPS yaw (heading) using ArduRover 4.1.0-dev firmware (downloaded mid-July 2020 from ArduPilot). Prior to this, the magnetometer based compass values provided wildly inaccurate results at times, likely due to interference from the rotating engine, ignition, and mower blades. Using a combination of three uBlox ZED-F9P GPS boards from ArduSimple (SimpleRTK2B), in a fixed base/moving base/rover configuration, the flight controller can calculate heading based on positional comparison of the mower's antennas, mounted about 30" apart. Flight controller is a ProfiCNC/Hex Cube Orange on a Pixhawk 2.1 carrier board. Parameters of interest: AHRS_EKF_TYPE = 3 EK3_ENABLE = 1 EK3_MAG_CAL = 6 GPS_AUTO_CONFIG = 1 GPS_DRV_OPTIONS = 1 GPS_TYPE = 17 GPS2_TYPE = 18 GPS_RATE_MS = 100 GPS_RATE_MS2 = 100 GPS_POS1_Y = -0.366 GPS_POS2_Y: 0.366 SERIAL1_PROTOCOL = 2 (MAVLink 2 telemetry)