Created email_dev recipe with mailcatcher and mail_view.

I'm not sure if you necessarily want this recipe, but it's another one we use and I figured I'd contribute back.

It adds two gems that we use for developing mailers in rails apps in development mode without having to actually send emails all over the place. Either gem is useful, and they can also be used side-by-side. There's [mailcatcher](https://github.com/sj26/mailcatcher) and [mail_view](https://github.com/37signals/mail_view).

Here's a good article that summarizes using both of them:
http://www.mikeperham.com/2012/12/09/12-gems-of-christmas-4-mailcatcher-and-mail_view/