Get a category

[sjehuda]

Do not attempt to iterate categories because there is only a category.

[sjehuda]

First posted at https://github.com/imattau/atomtopubsub/pull/2

[edhelas]

https://www.ietf.org/rfc/rfc4287.html#section-4.1.2

atom:entry elements MAY contain any number of atom:category elements.

[sjehuda]

feedparser stores only one category in attribute "category", if found, and the rest of them may be inside attribute "tags". See entries[i].tags.