Small improvements of auto stash component

- airline can be set in model
- fallback if there is no airline, but livery code

src/blackmisc/simulation/aircraftmodel.h

@@ -185,6 +185,9 @@ namespace BlackMisc
             //! Airline ICAO code
             const Aviation::CAirlineIcaoCode &getAirlineIcaoCode() const { return m_livery.getAirlineIcaoCode(); }
 
+            //! Set airline ICAO code designator
+            bool setAirlineIcaoDesignator(const QString &designator) { return m_livery.setAirlineIcaoCodeDesignator(designator); }
+
             //! Airline ICAO code designator
             const QString &getAirlineIcaoCodeDesignator() const { return m_livery.getAirlineIcaoCode().getDesignator(); }