[xswiftbus] Plane View Menu

FSX/P3D have a nice feature to follow a remote aircraft with the camera.
X-Plane was missing this feature, since for X-Plane the remote aircrafts
are not known. However, from a plugin point of view, we know them and where
they are. So we can manually control the camera and provide a similar
feature.
This is still very simple. As soon as you move the mouse, the PoV angle will
change. In future updates, it should be change only while the right mouse
button is pressed.

src/xswiftbus/traffic.h

@@ -15,7 +15,9 @@
 #include "dbusobject.h"
 #include "datarefs.h"
 #include "terrainprobe.h"
+#include "menus.h"
 #include "XPMPMultiplayer.h"
+#include "XPLMCamera.h"
 #include <XPLM/XPLMDisplay.h>
 #include <functional>
 #include <utility>
@@ -53,6 +55,9 @@ namespace XSwiftBus
             return s;
         }
 
+        //! Set plane view submenu
+        void setPlaneViewMenu(const CMenu &planeViewSubMenu) { m_planeViewSubMenu = planeViewSubMenu; }
+
         //! Called by XPluginStart
         static void initLegacyData();
 
@@ -113,9 +118,11 @@ namespace XSwiftBus
 
         void emitSimFrame();
         void emitRemoteAircraftData(const std::string &callsign, double latitude, double longitude, double elevation, double modelVerticalOffset);
+        void orbitRemotePlane(const std::string &callsign);
 
         static int preferences(const char *section, const char *name, int def);
         static float preferences(const char *section, const char *name, float def);
+        static int orbitPlaneFunc(XPLMCameraPosition_t *cameraPosition, int isLosingControl, void *refcon);
 
         struct Plane
         {
@@ -142,6 +149,10 @@ namespace XSwiftBus
         std::unordered_map<void *, Plane *> m_planesById;
         std::chrono::system_clock::time_point m_timestampLastSimFrame = std::chrono::system_clock::now();
 
+        CMenu m_planeViewSubMenu;
+        std::unordered_map<std::string, CMenuItem> m_planeViewMenuItems;
+        std::string m_planeViewCallsign;
+
         int getPlaneData(void *id, int dataType, void *io_data);
         static int getPlaneData(void *id, int dataType, void *io_data, void *self)
         {