create open/closed toggles for job posts

We get lots of requests for people to delete their jobs. I think it's interesting to keep the information around for historic purposes. What might work is some ability to mark a job as "filled" that would change the way it is themed on the site and remove it from the default /jobs list.

Some example jobs that have been cleared out, removing their historic value: http://groups.drupal.org/node/79874 http://groups.drupal.org/node/75678