Improve sorting

pglab/CustomDataRole.h

@@ -23,6 +23,7 @@ enum CustomDataRole {
 	CustomDataTypeRole = Qt::UserRole, ///< Requist the basic type of the value
 	CustomReferencedTypeRole, ///<
     CustomDataMeaningRole,
+    CustomSortRole, // return data in a form that will sort correctly
     // Add other enum before this one as we might want to have multiple hidden values
 	FirstHiddenValue, ///< Used to request value from a model which is not handed to the view
 };