Allow moderation exemption to be configurable by role (drupal 5)

I had the need for a permission to allow moderation exemption and created a patch for d5 based on the d6 patch in the discussion here: http://drupal.org/node/198825

My patch for d5 is attached. It needs to be tested on a fresh install (which I'll do and report back on when I have time). Also, I don't upload patches often and this was the first one I ran using a bzr diff - so please yell at me if it doesn't apply correctly and I'll try to figure out where I went wrong.