refs #748, add airport completers

* in flight plan
* in login
* utility functions

src/blackmisc/aviation/airportlist.h

@@ -50,9 +50,11 @@ namespace BlackMisc
             //! Find first station by callsign, if not return given value / default
             CAirport findFirstByIcao(const CAirportIcaoCode &icao, const CAirport &ifNotFound = CAirport()) const;
 
+            //! All ICAO codes
+            QStringList allIcaoCodes(bool sorted) const;
+
             //! Reads the airport list from database JSON
             void convertFromDatabaseJson(const QJsonArray& json);
-
         };
     } //namespace
 } // namespace