Initial commit of plugin

git-svn-id: https://plugins.svn.wordpress.org/gravity-forms-braintree/trunk@897834 b8457f37-d9ea-0310-8a92-e5e31aec5664
Updated readme

git-svn-id: https://plugins.svn.wordpress.org/gravity-forms-braintree/trunk@897836 b8457f37-d9ea-0310-8a92-e5e31aec5664