Reflecting discussed changes for interpolation performance refs #386

(based on FSX testing)
* Only send changed situation to SIM
* Split sending of parts / situations
* Only send parts with a reduced frequency (means slower as positions)
* Mark geodetic height as null for default values (the value is usually unavailable)
* Fixed altitude to MSL for network data
* Trace which aircrafts support aircraft parts via network
* Renamed insert_fron push_front (as proposed by Roland)

Status quo / lessons learnt
* On slower PCs jitter is still noticed for interpolated aircraft.
* Running interpolation in an independent process (aka core, not in GUI) reduced load dependencies
  => it seems to make sense to run driver in own thread
* The onGround flag in parts seems clumsy as it required to retrieve parts for position updates
* In interpolation performance really matters

src/blackmisc/simulation/simulatedaircraftlist.cpp

@@ -55,6 +55,17 @@ namespace BlackMisc
             return this->findBy(Predicates::MemberValid(&CSimulatedAircraft::getPilot)).transform(Predicates::MemberTransform(&CSimulatedAircraft::getPilot));
         }
 
+        CCallsignList CSimulatedAircraftList::getCallsignsWithSyncronizedParts() const
+        {
+            CCallsignList csl;
+            for (const CSimulatedAircraft &aircraft : (*this))
+            {
+                if (!aircraft.isPartsSynchronized()) { continue; }
+                csl.push_back(aircraft.getCallsign());
+            }
+            return csl;
+        }
+
         CAircraftList CSimulatedAircraftList::toAircraftList() const
         {
             CAircraftList al;