Ref T259, Ref T243 improved utility functions so parts can be guessed in interpolator

* engine count
* aligned naming to "getEnginesCount"
* formatting

src/blackmisc/aviation/aircraftenginelist.h

@@ -59,6 +59,9 @@ namespace BlackMisc
             //! \remark 1 based, not 0 based
             void setEngineOn(int engineNumber, bool on);
 
+            //! Copy one engine multiple times (number) and set the number of engines to number
+            void setEngines(const CAircraftEngine &engine, int engineNumber);
+
             //! Init some engines
             void initEngines(int engineNumber, bool on);