* Add canedit hook, allowing arbitrary controls over when a page can be••• edited.
* Move code forcing signing before edit to a new "signinedit" plugin, and
code checking for locked pages into a new "lockedit" plugin. Both are
enabled by default.
* Remove the anonok config setting. This is now implemented by a new
"anonok" plugin. Anyone with a wiki allowing anonymous edits should
change their configs to enable this new plugin.
* Add an opendiscussion plugin that allows anonymous users to edit
discussion pages, on a wiki that is otherwise wouldn't allow it.
* Lots of CGI code reorg and cleanup.