* Added __HIDDENCAT__ feature, to hide categories from the box at the bottom of the...

* Added __HIDDENCAT__ feature, to hide categories from the box at the bottom of the member pages depending on special text on the category page.
* Added page_props backend, generic parser-driven page properties which, when changed, invalidate the cache of backlinked pages on any links table. Could be used to add overlays to images depending on their deletion status, or to add icons to articles based on category membership.
* Refactored double-underscore handling in the parser.
* Moved CoreParserFunctions registration to CoreParserFunctions.