Fix email templates To/From to conform to RFC 5322

This removes the duplicate mention of the email address in the To: and
From: headers of templates, because the @ character is not allowed as
part of an atom.

It would only be allowed if the email address in the name part was quoted.

Details: http://tools.ietf.org/html/rfc5322#section-3.2.3

This fixes display and reply problems in Apple Mail which would display `foo@` for the bad example given below and build a wrong reply address `"foo@" <example.org foo@example.org>`.

Examples:
```
[BAD] foo@example.org <foo@example.org>
[OK] <foo@example.org>
[OK] "foo@example.org" <foo@example.org>
```