updated readme

git-svn-id: https://plugins.svn.wordpress.org/bbpress-notify-nospam/trunk@1043677 b8457f37-d9ea-0310-8a92-e5e31aec5664
adjusted stable tag and tested-up-to in readme.txt file

git-svn-id: https://plugins.svn.wordpress.org/bbpress-notify-nospam/trunk@1043684 b8457f37-d9ea-0310-8a92-e5e31aec5664