minor updates

git-svn-id: http://plugins.svn.wordpress.org/wordpress-social-login@657639 b8457f37-d9ea-0310-8a92-e5e31aec5664
fix callback_url

git-svn-id: http://plugins.svn.wordpress.org/wordpress-social-login@657640 b8457f37-d9ea-0310-8a92-e5e31aec5664
fix tumblr auth

git-svn-id: http://plugins.svn.wordpress.org/wordpress-social-login@657648 b8457f37-d9ea-0310-8a92-e5e31aec5664