banner and readme update

git-svn-id: https://plugins.svn.wordpress.org/pmpro-bbpress/trunk@859489 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fixed generation of URLs &noaccess=1. The old URLs could sometimes lead to 404 pages. (Thanks, bfintal on the WordPress.org forums.)wq

git-svn-id: https://plugins.svn.wordpress.org/pmpro-bbpress/trunk@859526 b8457f37-d9ea-0310-8a92-e5e31aec5664