Can we do these things in LinksSQL?

1. Give users editing permissions to specified categories, ie: the right to add, delete and modify links within their category or categories only.
2. Have more than one 'editor' in a category.
3. Track editor actions, so we can work out what they have done (and if necessary, reverse it).

We want to have something a bit like the Open Directory editors system, where editors are trusted within their own categories and can gradually expand their interests upwards and outwards.