refs #568, improved validation and handling

* invalid models can be highlighted on stash
* selection mode can be toggled between single/multi selection (where applicable)
* color for highlighting can be set
* finetuning of menus

src/blackmisc/simulation/aircraftmodellist.h

@@ -90,6 +90,9 @@ namespace BlackMisc
             //! Validate for publishing
             CStatusMessageList validateForPublishing() const;
 
+            //! Validate for publishing
+            CStatusMessageList validateForPublishing(CAircraftModelList &invalidModels) const;
+
             //! To database JSON
             QJsonArray toDatabaseJson() const;