Proposed Cleanup

So. The MIT server is running off of pull-645-rebase. People made tweaks and did dev work on the server, which I committed to a child branch, dirty-server. This pull request attempts to bring us back in line with main, with some MIT-specific changes omitted (in particular, the splash-class-registrations@ hack will stay on the server, as will django-debug-toolbar until it is reviewed further). Is this acceptable?