SITL: Fix a number of includes that were coming in via AP_Airspeed

libraries/SITL/SIM_Aircraft.h

@@ -28,6 +28,7 @@
 #include "SIM_Gripper_EPM.h"
 #include "SIM_Parachute.h"
 #include "SIM_Precland.h"
+#include <Filter/Filter.h>
 
 namespace SITL {
 

libraries/SITL/SIM_Gimbal.cpp

@@ -22,6 +22,8 @@
 
 #include "SIM_Aircraft.h"
 
+#include <AP_InertialSensor/AP_InertialSensor.h>
+
 extern const AP_HAL::HAL& hal;
 
 namespace SITL {

libraries/SITL/SIM_Sailboat.cpp

@@ -22,6 +22,7 @@
 
 #include "SIM_Sailboat.h"
 #include <AP_Math/AP_Math.h>
+#include <AP_AHRS/AP_AHRS.h>
 #include <string.h>
 #include <stdio.h>