Ref T180, remove aircraft

* utility function getAllCallsigns
* allow to trace sendId (in removing)
* make sure aircraft are not added again by upfront clearing lists

src/plugins/simulator/fsxcommon/simconnectobject.cpp

@@ -7,6 +7,7 @@
  * contained in the LICENSE file.
  */
 
+#include "simconnectobject.h"
 #include "simconnectobject.h"
 #include "blackmisc/simulation/interpolatormulti.h"
 
@@ -128,6 +129,11 @@ namespace BlackSimPlugin
             return getSimObjectForObjectId(objectId).getCallsign();
         }
 
+        CCallsignSet CSimConnectObjects::getAllCallsigns() const
+        {
+            return CCallsignSet(this->keys());
+        }
+
         CSimConnectObject CSimConnectObjects::getSimObjectForObjectId(DWORD objectId) const
         {
             for (const CSimConnectObject &simObject : this->values())