Remove mezzanine.accounts

We weren't using it and it got in the way of basic admin modding
Configure users list display
Allow filtering on rsvp and staff status
Enable search
Set fields for change page; make them readonly
Add food offer inline
Configure FoodOffer admin (inline and own)
Use get_reply_date in list view
Fix food offer search
Remove description from food list
Merge pull request #8 from exonian/feature/admin

Feature/admin