Add a menu tab to admin/content

I just found this module, at first glance there does not seem to be a way to access the queues without typing the path directly.  I've updated the view to provide a menu tab to access the queues without typing the path directly to the content list.

![queues listing site-install](https://f.cloud.github.com/assets/810903/2378583/642f67e6-a890-11e3-8b98-ef033fe89b69.jpg)