newsfeed/atom: Wrap the name of the author in a name element.

This fixes an validation error (http://validator.w3.org/feed).

According to http://tools.ietf.org/html/rfc4287 the atom:author
element contains a person construct, that is it contains at least the
name element.

No further elements of the person construct are added, as there is no
representation for them in the current Feed type.