Asirra captcha support for CommunityServer

Project Description
This adds the Asirra human interactivity proof control support to CommunityServer 2007.

Asirra is a human interactive proof that asks users to identify photos of cats and dogs. It's powered by over three million photos from our unique partnership with Petfinder.com.
(http://research.microsoft.com/asirra/ <- More here.

Plans
I am thinking about playing with Silverlight and Asirra, so you could pick cats from a nicer UI.

Example in action
http://melborp.net/pages/example-post-to-test-asirra-plugin-for-community-server-in-action.aspx (the blog is in estonian - so please test on this example post).