Move base to layouts, add header/footer includes
Use chpass principal of chpass/$hostname

Loading from a settings file is probably cleaner, but this lets us share
a settings.py file between earthquake and dev-earthquake.
Remove captcha from change_password

Users have already auth'd with CalNet, so we're not really concerned
about ensuring the user is human.

We might bring this back soon for the login page, but removing the code
for now.
Clean up URLs, remove group_accounts_only

- Use dashes instead of underscores in URLs
- Remove optional trailing slash in URLs
- Remove group_accounts_only URL (instead just render the template when
  necessary instead of redirecting to it)