Improved support from removing rows in crud tabs.

It can handle now complex selections and reports back errors encountered
when removing the rows fails.

pglab/CustomDataRole.h

@@ -3,10 +3,21 @@
 
 #include <Qt>
 
+///	Returned by a model when asked for CustomReferencedTypeRole
+///
+/// Models will probably only be asked this for columns for which they returned
+/// Oid_Oid for the CustomDataTypeRole
+enum class ReferencedType {
+	PgType,
+	PgNamespace,
+	PgRole
+};
+
 enum CustomDataRole {
-	CustomDataTypeRole = Qt::UserRole,
+	CustomDataTypeRole = Qt::UserRole, ///< Requist the basic type of the value
+	CustomReferencedTypeRole, ///<
 	// Add other enum before this one is we might want to have multiple hidden values
-	FirstHiddenValue,
+	FirstHiddenValue, ///< Used to request value from a model which is not handed to the view
 };
 
 #endif // CUSTOMDATAROLE_H