[Bug 972269] Add calls to action to auth page.

I added two sections to the right of the login form, with links to the get involved page and the AAQ. These only show if you did not land on the page with the "wants to be a contributor" flag set. I also stole some images from the get involved page, because it looked boring.

It looks like this:

![shot_24481](https://f.cloud.github.com/assets/305049/2253464/27adfd9a-9dbf-11e3-8dfa-133f578d5628.png)

r?