Plane: avoid some float conversion warnings
APM_Control: avoid some float conversion warnings
AP_ADC_AnalogSource: avoid some float conversion warnings
AP_Airspeed: avoid some float conversion warnings
AP_Baro: avoid some float conversion warnings
AP_GPS: avoid some float conversion warnings
HAL_Empty: avoid some float conversion warnings
HAL_PX4: avoid some float conversion warnings
build: disable some compiler errors for now

this needs more work, but allows us to build with upstream PX4
Firmware now
Copter: Don't use land detector to stop stabilizing in stabilize