* Remove compatability code in `loadindex` to handle old index data layouts.
* Make pagespecs match relative by default? (see [[discussion]])
* Flip wikilinks? (see [[todo/link_plugin_perhaps_too_general?]] and [[todo/do_not_make_links_backwards]])
-* YADA format setup files per default?
* Enable tagbase by default (so that tag autocreation will work by default).
Note that this is already done for wikis created by `auto-blog.setup`.
* [[tips/html5]] on by default (some day..)
* Remove support for old `.ikiwiki/comments_pending` from comment plugin.
-* Use yaml formatted setup files by default. (Not too compatability breaking
- really.)
In general, we try to use [[ikiwiki-transition]] or forced rebuilds on
upgrade to deal with changes that break compatability. Some things that