ikiwiki now supports subscribing to pages on wikis with a subversion
backend. Subscribers will be mailed commit diffs.

Some changes are needed to ikiwiki configs to support this:

* A new `--adminemail` config option has been added, that is used for both
  this and for sending user subscription mails, so should be configured on
  any wiki that uses either feature. 
* `--svnpath` needs to be set to location of your wiki inside its
  subversion repository. It defaults to "trunk", which will work for many
  layouts.
* A new `--notify` config option should be passed to ikiwiki when it's run
  as a svn commit hook, to enable it sending the subscription mails.
* `--svnrepo` is actually supported and used now, so should be set to the
  subversion repository directory.

[[ikiwiki.setup]] has been updated accordingly.

This is the last major change planned before the first official release of
ikiwiki. The main remaining issue blocking that release is the resolution
of what to do about HTML XSS [[security]] issues.