Fix typo in plugin short description

git-svn-id: https://plugins.svn.wordpress.org/wp-google-authenticator/trunk@1026232 b8457f37-d9ea-0310-8a92-e5e31aec5664
Highlight compatibility with Authy

git-svn-id: https://plugins.svn.wordpress.org/wp-google-authenticator/trunk@1026234 b8457f37-d9ea-0310-8a92-e5e31aec5664