- Realized I made a boo-boo by adding the keyword_id column that allows
per-category custom fields to the wrong table. Moved it to ca_attributes
and changed pl/pgsql and tcl api's accordingly.
- Create index in ca_attributes to improve speed. Still need to assess
where else we need indices.
- Changed API a bit. A couple functions named _exists_p were not boolean
at all, hence confusing.
- Updated user/admin files to reflect changes.
- Adding of custom fields now lets site-wide admin add site-wide custom
fields, otherwise only package-wise custom-fields.
- Improved fields UI. Needs more work.
- Updated Tcl callbacks.
