vtol fixes:

- mc pos control: publish attitude setpoint when vtol is in trans mode
- fw att control: do not publish attitude setpoint when in transition mode
- introduce flag in_transition_mode in vehicle status message for vtol
- improve tiltrotor code based on flight testing

src/modules/fw_att_control/fw_att_control_main.cpp

@@ -941,7 +941,7 @@ FixedwingAttitudeControl::task_main()
 					att_sp.thrust = throttle_sp;
 
 					/* lazily publish the setpoint only once available */
-					if (!_vehicle_status.is_rotary_wing) {
+					if (!_vehicle_status.is_rotary_wing && !_vehicle_status.in_transition_mode) {
 						if (_attitude_sp_pub != nullptr) {
 							/* publish the attitude setpoint */
 							orb_publish(ORB_ID(vehicle_attitude_setpoint), _attitude_sp_pub, &att_sp);