Log Message:
Update to 4.0. From the changelog:

* Support for Atom 1.0.
* Support for iTunes extensions.
* Support for dc:contributor.
* Universal Feed Parser now captures the feed's namespaces. See
  Namespace Handling for details.
* Lots of things have been renamed to match Atom 1.0 terminology.
  issued is now entries[i].published, modified is now entries[i].updated,
  and url is now href everywhere. You can still access these elements
  with the old names, so you shouldn't need to change any existing
  code, but don't be surprised if you can't find them during
  debugging.
* category and categories have been replaced by tags, see feed.tags
  and entries[i].tags. The old names still work.
* mode is gone from all detail and content dictionaries. It was
  never terribly useful, since Universal Feed Parser unescapes
  content automatically.
* entries[i].source is now a dictionary of feed metadata as per
  section 4.2.11 of RFC 4287. Universal Feed Parser no longer
  supports the RSS 2.0's source element.
* Content in unknown namespaces is no longer discarded (bug 993305)
* Lots of other bug fixes.