Move jquery to the head

So that /unregister may include javascript that references $.
Add unregister page

Confirming a fresh registration is enough be removed from the directory.
Most of this code is adapted from TS-Browser.
Make footer sticky

http://ryanfait.com/resources/footer-stick-to-bottom-of-page/
Rate-limit verification code requests

10s client-side rate limit.
remove shuttleworth logo