Email notificaitons for mentions#66

As a Threaded Comments user, when someone pings me in a comment, I need to get an email (not just a notification in the Notifications Tab), because I am not in the habit of monitoring my Trello Notificaitons Tab.

It’s possible this is already covered by the request to get notifications, and it’s understood that my notifications will be processed into emails, depending on my Trello settings. But i wanted to make sure.