Issue 3525 - Sort works by date on stats page when hit counts are disabled

https://code.google.com/p/otwarchive/issues/detail?id=3525

Allow the user to sort by date when clicking the date sort option button on the Stats page.

Note that the visualization still shows the top 5 most recent works graphed against the number of hits when sorting by date. This is probably not the correct behavior when the user turned off hits in their preferences. However I'm not sure if it's part of this bug (or what to display instead).