Aggregator module does not correctly parse author data

According to http://tools.ietf.org/html/rfc4287#section-4.2.1 the atom:author tag is a Person construct. It can (as http://tools.ietf.org/html/rfc4287#section-3.2) has 3 children. Something like this is valid:

        <author>
                <name>John Doe</name>
                <email>johndoe@example.com</email>
        </author>

(both in feed source or each entry).

Currently Aggregator does not parse author tag, nor its children.

A consequence of this bug is if we have this:

        <summary>some data...</summary>
        <author>
                <name>John Doe</name>
                <email>johndoe@example.com</email>
        </author>

Then after the parsing, $feed->items[0]['summary'] contains erronous data:

        some data...
                John Doe</name>
                johndoe@example.com

It is because the parser does not process these tags.