revised readme

git-svn-id: https://plugins.svn.wordpress.org/birchschedule/trunk@986963 b8457f37-d9ea-0310-8a92-e5e31aec5664
revised readme

git-svn-id: https://plugins.svn.wordpress.org/birchschedule/trunk@986965 b8457f37-d9ea-0310-8a92-e5e31aec5664