Ref T370, added public removeAllRemoteAircraft

* protected clearAllRemoteAircraftData
* ISimulator::clearAllRemoteAircraftData no longer calls clearAllRemoteAircraftData (circular)

src/plugins/simulator/fs9/simulatorfs9.cpp

@@ -213,6 +213,8 @@ namespace BlackSimPlugin
             {
                 if (physicallyRemoveRemoteAircraft(cs)) { r++; }
             }
+
+            CSimulatorFsCommon::physicallyRemoveAllRemoteAircraft();
             return r;
         }