Make the page load for the review request page less jumpy.

When displaying a draft banner for either the review request or a
review, the page was a bit jumpy. We'd render the page and then display
the draft banners.

This change shows the draft banners right away, and even adds a nice
subtle slide in/out animation for the review draft banner at the top of the
window.

Tested in IE6 and Firefox. I tested the review request draft banner and the review draft banner on the review request page, diff viewer, and screenshot pages. I also made sure nothing broke when logged out or when viewing another user's review request.