refs #452, adjusted aircraft/aviation classes

* support for loading from datastore
* improved timestamp handling
* new color and country classes
* new attributes
* updates for missing parts in CUser

src/blackmisc/datastoreobjectlist.h

@@ -50,6 +50,9 @@ namespace BlackMisc
         //! Sort by timestamp
         void sortByKey();
 
+        //! All keys as string list
+        QStringList toDbKeyList() const;
+
         //! From DB JSON
         static CONTAINER fromDatabaseJson(const QJsonArray &array);