pycharm: use newer database driver.
see http://youtrack.jetbrains.com/issue/IDEA-91124
require django-social-auth, add to INSTALLED_APPS
events.views: add login_required.
(yes, this redirects to a login page that doesn't exist yet.)
pycharm: share project test runner
(works with pycharm 2.7.)
add /accounts/login/ url and view with Persona (aka BrowserID) login.
bring in filepath for path calculations, add a static/ directory
Make the sign-in button pretty.
persona-buttons.css is from
https://developer.mozilla.org/en-US/docs/Persona/branding
tests: don't use relative imports, as they break under test runners.
views.login: pass through the next-page information for redirect
views.login: fix open redirect.