Sorting by date added field

The sorting by Date Added appears to be sorting on the id field, not the actual date added field.

I'm sure for 99% of users, this is totally fine. In my case, I want to sort my exhibits by a specified date (each exhibit represents a different event and I want to list them chronologically). I'm doing a hacky thing and manually setting Date Added in the database to the event date. My events are listed in the proper descending order if I sort by Recent, but if I sort by Date Added it is sorting on id.

I've hacked in a fix (In ExhibitController, changed _getBrowseDefaultSort function so that the default case matches the recent case and except using 'a' instead of 'd'), so I'm good.

I don't think that this is ever an issue unless people are monkeying with Date Added in the database. Ideally it would be great to have more sorting options for exhibits, but if not, hopefully by at least posting this someone else will be saved from a lot of confusion.

Start in ExhibitController at _getBrowseDefaultSort, comparing the Date Added default case with the Recent case described in the issue. Confirm that sorting by Date Added uses the actual date-added field rather than the exhibit id, and verify that exhibits with manually set dates appear in chronological order.