returned (and not run in some cases) rather than the plugins directly
forcing a user to log in.
* opendiscussion: allow editing of the toplevel discussion page,
and, indirectly, allow creating new discussion pages.
links required meta to be run during scan, which complicated its data
storage, since it had to clear data stored during the scan pass to avoid
duplicating it during the normal preprocessing pass.
* If you used "meta link", you should switch to either "meta openid" (for
openid delegations), or tags (for internal, invisible links). I assume
that nobody really used "meta link" for external, non-openid links, since
the htmlscrubber ate those. (Tell me differently and I'll consider bringing
back that support.)
* meta: Improved data storage.
* meta: Drop the hackish filter hook that was used to clear
stored data before preprocessing, this hack was ugly, and broken (cf:
liw's disappearing openids).
* aggregate: Convert filter hook to a needsbuild hook.