Updated to use authorized_response approach
Merge pull request #221 from mdxs/upd_authorized

Updated to use authorized_response approach
Handle case in which email is None (as GitHub can provide)
Merge pull request #222 from mdxs/fix_create_user_db

Handle case in which email is None (as GitHub can provide)
Added  rel="nofollow" to order and filter links
Added Yandex.Metrika web analytics (http://metrica.yandex.com).
Fix Yandex Metrika field generation and added help-block.