update contributors

git-svn-id: https://plugins.svn.wordpress.org/dw-social-feed/trunk@815309 b8457f37-d9ea-0310-8a92-e5e31aec5664
update authors

git-svn-id: https://plugins.svn.wordpress.org/dw-social-feed/trunk@815310 b8457f37-d9ea-0310-8a92-e5e31aec5664