updated readme for WP 4.1

git-svn-id: https://plugins.svn.wordpress.org/paypal-donations/trunk@1048764 b8457f37-d9ea-0310-8a92-e5e31aec5664
committing v1.8.7

git-svn-id: https://plugins.svn.wordpress.org/paypal-donations/trunk@1048766 b8457f37-d9ea-0310-8a92-e5e31aec5664