Feature/django 1.5

Hi @dfeeney,

The goal of this branch was to update Viewshare to Django 1.5 and that seems to have been accomplished. However, this branch also contains some dataset editor work that hasn't been merged into LC's develop branch yet. For that reason this pull request looks a little more complicated than I intended.

There are a few things to note regarding the upgrade to Django 1.5:
* The 'ALLOWED_HOSTS' setting is required now. I set this in viewshare/settings.py but chances are we'll want to set it in the viewshare_site project as the domain is specific to us.
* The upgrade from django-announcements 0.1.2 to 1.0.2 was not clean. Specifically the app used to use South migrations and doesn't anymore. Also, while dropping migrations they also changed the model. I think our upgrade path involves two SQL commands on the beta database. Then we can sync the database and build the new announcements tables. The two SQL commands are:
 1. DROP TABLE announcements_announcement;
 2. DELETE FROM south_migrationhistory where app_name = 'announcements';
* Right now viewshare is still using django-registration 0.8. I modified our moderated_registration code so it would work with Django 1.5. The next step is to upgrade django-registration to 1.0 and rewrite our moderated_registration code. I wanted to do this in two steps so that I would be sure to have something ready for tomorrow's beta release.

Good luck with the beta deployment tomorrow. It's a potentially awkward one with all the changes and new requirements. Please let me know if you have any questions.