ArduPlane: implement HAL::Callbacks

Also removes includes for each board since they are not necessary
anymore.

ArduPlane/ArduPlane.cpp

@@ -908,19 +908,4 @@ void Plane::update_optical_flow(void)
 }
 #endif
 
-/*
-  compatibility with old pde style build
- */
-void setup(void);
-void loop(void);
-
-void setup(void)
-{
-    plane.setup();
-}
-void loop(void)
-{
-    plane.loop();
-}
-
-AP_HAL_MAIN();
+AP_HAL_MAIN_CALLBACKS(&plane);

ArduPlane/Plane.h

@@ -104,14 +104,6 @@
 
 #include "Parameters.h"
 
-#include <AP_HAL_AVR/AP_HAL_AVR.h>
-#include <AP_HAL_SITL/AP_HAL_SITL.h>
-#include <AP_HAL_PX4/AP_HAL_PX4.h>
-#include <AP_HAL_FLYMAPLE/AP_HAL_FLYMAPLE.h>
-#include <AP_HAL_Linux/AP_HAL_Linux.h>
-#include <AP_HAL_Empty/AP_HAL_Empty.h>
-#include <AP_HAL_VRBRAIN/AP_HAL_VRBRAIN.h>
-
 /*
   a plane specific arming class
  */
@@ -134,15 +126,17 @@ protected:
 /*
   main APM:Plane class
  */
-class Plane {
+class Plane : public AP_HAL::HAL::Callbacks {
 public:
     friend class GCS_MAVLINK;
     friend class Parameters;
     friend class AP_Arming_Plane;
 
     Plane(void);
-    void setup();
-    void loop();
+
+    // HAL::Callbacks implementation.
+    void setup() override;
+    void loop() override;
 
 private:
     // key aircraft parameters passed to multiple libraries