Do not allow the user to modify/delete objects designed for logging (change tracking, error log, information log, etc.)

SVN:trunk[440]

core/dbobject.class.php

@@ -76,6 +76,12 @@ abstract class DBObject
 		}
 	}
 
+	// Read-only <=> Written once (archive)
+	static public function IsReadOnly()
+	{
+		return false;
+	}
+
 	public function RegisterAsDirty()
 	{
 		// While the object may be written to the DB, it is NOT possible to reload it