2.15 release

git-svn-id: https://plugins.svn.wordpress.org/really-simple-facebook-twitter-share-buttons/trunk@802336 b8457f37-d9ea-0310-8a92-e5e31aec5664
2.16 release

git-svn-id: https://plugins.svn.wordpress.org/really-simple-facebook-twitter-share-buttons/trunk@804773 b8457f37-d9ea-0310-8a92-e5e31aec5664