Safely initialize Drupal.Panels javascript object

In the event where panels.js or panels-base.js is called after display_editor.js (I managed to do this by calling $renderer::add_meta() a second time in a specialized renderer class) all of the drag and drop methods are wiped out because Drupal.Panels is re-initialized to an empty object {}. I propose initializing Drupal.Panels in the same manner the the global Drupal object is initialized:

Drupal.Panels = Drupal.Panels || {};