Add issuer to generated account

git-svn-id: https://plugins.svn.wordpress.org/wp-google-authenticator/trunk@851954 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update stable tag

git-svn-id: https://plugins.svn.wordpress.org/wp-google-authenticator/trunk@851957 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update changelog

git-svn-id: https://plugins.svn.wordpress.org/wp-google-authenticator/trunk@851960 b8457f37-d9ea-0310-8a92-e5e31aec5664