Added api for custom timetable events

lib/api/webuntis/queries/getRooms/getRooms.dart

@@ -17,7 +17,7 @@ class GetRooms extends WebuntisApi {
       log("Failed to parse getRoom data with server response: $rawAnswer");
     }
 
-    throw Exception("Failed to parse getRoom server response");
+    throw Exception("Failed to parse getRoom server response: $rawAnswer");
   }
 
 }