== New: _feed-max-size_ and _feed-max-size-ips_

This is all because LiveJournal has undocumented size limits on
incoming syndication feeds, limits that DWiki can easily blow past.
Since I actually wanted LiveJournal to be able to get syndication
feeds from me, DWiki has grown two new configuration settings.

_feed-max-size_ is an integer kilobytes. It is a rough limit on how
large any feed can be; once DWiki generates a feed that is this many
kilobytes or larger it stopps adding more entries, regardless of the
setting for _atomfeed-display-howmany_. If unset, there is no size
limit.

_feed-max-size-ips_ restricts _feed-max-size_ to the whitespace
separated list of IP addresses or tcpwrappers style IP address
prefixes (eg '_66.150.15._' to get all of ((66.150.15.*))).
Syndication fetches from other addresses will behave as if there was
no _feed-max-size_.

Strictly speaking, _feed-max-size_ limits only the size of the
_atom::pages_ or _atom::comments_ output to that size. Whatever else
is tacked on to make up a feed (hopefully not very big) will add some
extra size.

Moral: undersize _feed-max-size_ a bit. For LiveJournal, the limit is
apparently 150 kilobytes (currently), so setting it to '120' or so
should provide a comfortable safety margin.

Although I'm not entirely fond of this (to put it one way), the
documentation has been updated appropriately, making this feature more
or less official.