We used to use Django templates and the Sites framework. At some point we
stopped, but this was leftover. The site_name no longer gets set properly.
It's probably a config issue, but not one I want to deal with right before
release, so I'm hardcoding it to link to the prod edx.org site until we
 can sort what's what in the morning.

Cleaned up activation pages. Added "Log In" link to notice when anonymous user tries to enroll in course.

Registering now temporarily logs you in. A message is displayed on the dashboard, reminding you to activate your account. Logging in shows a reminder about activating.