Attach is called before all the setters

[irfantusneem]

controller.isAttachAware should be before checking mappings.

    if (controller is AttachAware) {
      var taskId = tasks.registerTask();
      Watch watch;
      watch = scope.watch('1', // Cheat a bit.
          (_, __) {
        watch.remove();
        tasks.completeTask(taskId);
      });
    }

    if (ref.mappings.isNotEmpty) {
      if (nodeAttrs == null) nodeAttrs = new _AnchorAttrs(ref);
      _createAttrMappings(controller, scope, ref.mappings, nodeAttrs, formatters, tasks);
    }