Update plugin to support translation

git-svn-id: https://plugins.svn.wordpress.org/regnomail/trunk@885682 b8457f37-d9ea-0310-8a92-e5e31aec5664
update readme.txt

git-svn-id: https://plugins.svn.wordpress.org/regnomail/trunk@885684 b8457f37-d9ea-0310-8a92-e5e31aec5664