ChangedModel in ownAircraft context was not really used.

However, there are cases where the "own model" is changed via own model context, mostly in the emulated driver.

* made changedModel -> ps_changedModel a "private" signal
* connected it to simulator context
* used identifier to avoid roundtrips

So the "ownAircraftModelChanged" signal of the simulator context is to be used

src/blackcore/context/contextownaircraft.h

@@ -104,9 +104,6 @@ namespace BlackCore
             //! Own pilot (aka the swift user) changed
             void changedPilot(const BlackMisc::Network::CUser &pilot);
 
-            //! Changed aircraft model
-            void changedModel(const BlackMisc::Simulation::CAircraftModel &model);
-
             //! Aircraft has been moved from one location to another (changed scenery)
             void movedAircraft();