Add login styling

Adds styling to the login window (consistent with the rest of the site), and includes the otherwise not included header toolbar. Fixes #24.

Works for both '/newslogin' and '/login', even though '/login' is not reachable from the site and redirects nowhere after logging in.

Doesn't work for '/submit' when you're not logged in though, as that window shows two forms, a create account and a login form. However, it should be easy to refactor this patch afterwards to include that also, and I'm happy to do it if you'd like.