refs #649, further fixes and improvements

* call of non-virtual function in ctor
* use getCopy
* return number of merged models
* change current simulator in model set loader (fixes infinite loop: change data -> signal -> change data).

src/blackmisc/simulation/aircraftmodelloader.h

@@ -136,9 +136,6 @@ namespace BlackMisc
             //! Cache timestamp
             QDateTime getCacheTimestamp() const;
 
-            //! Make sure cache is syncronized
-            bool syncronizeCache();
-
             //! Any cached data?
             bool hasCachedData() const;