added profile URL filter

git-svn-id: https://plugins.svn.wordpress.org/affiliates/trunk@809368 b8457f37-d9ea-0310-8a92-e5e31aec5664
added note on new filter

git-svn-id: https://plugins.svn.wordpress.org/affiliates/trunk@809369 b8457f37-d9ea-0310-8a92-e5e31aec5664