DWiki can now generate Atom feeds for recently changed pages and
recently made comments, either for the entire DWiki or for some
subtree of it. For comments, this can be down to an individual
article.

At the moment, pages in the Atom feed are rendered without macros
except for _CutShort_, for efficiency reasons. All of the links
are turned into absolute links (with http:// et al), since this is
basically required. Nulled-out macros produce a small message to that
effect in the generated content, so that people reading the Atom feed
can tell that something is going on.
{{CutShort}}

Atom feeds are implemented as two new views, 'atom' and
'atomcomments', with a associated pile of new renderers. Unfortunately
the requirements of the Atom XML format make it all but impossible to
reuse standard renderers to display the content of things, because all
the actual HTML has to be escaped into oblivion. (Plus, bonus absolute
links.)

ChrisSiebenmann doesn't like the view name 'atomcomments' and may come
up with a better one sometime.

There is a new _atom::feeds_ renderer that creates the core of a feed
toolbar. (ChrisSiebenmann decided that this fit badly into the page
toolbar, which is for things that the browser can show you
natively. Atom feeds are a different sort of tool.)

Limitations:
* Atom feeds don't handle non-plain-ASCII in the wikitext. XML
  requires things to be converted to HTML entities, even if we label
  it as utf-8 (I believe), and we don't know how to do that unless we
  take wild swings at the character set.
* If the wiki is running on a non-standard port, your guess is as good
  as ChrisSiebenmann's as to what happens next. A couple of feed
  readers seem to want the port not to be there (liferea for Linux
  pukes if it is there, NetNewsWire for OS X is okay if it's not), so
  we currently omit it.

The Atom feed is almost but not quite 100% valid. The invalid bit is
that the latest Atom RFC has changed the tags used for dates; DWiki
generates both old and new date tags, which is invalid in either
view.