Rollback #523492 by schildi: write a hook_uninstall for category (this was written for the D5 branch of category, which is currently unmaintained).

#158598 by JirkaRybka: a massive collection of bug fixes, D6 upgrades, and performance / usability improvements and other tasks for the category package. This commit includes patches from the following threads:
 - #370641: Port category_views to D6
 - #370633: Port category_breadcrumb to D6
 - #484624: Fix all broken category/container previews, and add category_display defaults
 - #481280: Generated menu items vs. menu administration and weights
 - #457688: Get rid of Menu wrapper, moving functionality to category_menu
 - #484084: Update README.txt and friends
 - #483978: Remove t() from database schema descriptions
 - #501378: PERFORMANCE! Central caching for category API functions
 - #521680: Missing argument error on category/### paths
 - #521714: Missing JavaScript file in Taxonomy wrapper
Lots and lots of thanks go to JirkaRybka for this monumental cleanup effort.

457590 by JirkyRybka: change category_resave to use the batch API, to have an admin page instead of a block, and to have improved usability.

  manually installed after installing category. This is due to difficulties
  with having the wrapper files present when installing Drupal.
- Include .install files in wrapper install / uninstall script.
- Make the 'category' and 'container' node types get their default status /
  commenting / theme settings configured properly at install time.

  wrapper, and needed by some contrib modules.

  category_display_cont_load() in category_rss_item().

  appear when previewing a container (and category?).

  taxonomy_render_nodes() functions to the taxonomy wrapper, apparently some
  contrib modules depend on them.

  container has no assigned node types defined.
- Output the name of each container on 'admin/content/category' as a link.
- For the message on 'admin/content/types/_type_' indicating that a node type
  is a container and cannot be changed, properly use format_plural().
- fix all AJAX forms to use form_set_cache() instead of cache_set(), in
  conformance with the updates introduced in Drupal 6.4 core.
- New feature for category_menu: allow admins to choose the menu in which to
  populate auto-generated menu links for each container. If admins choose
  'default', then the normal book-module-style behaviour still applies, i.e.
  menu links are put into a 'hidden' menu called 'category-toc-_cnid_'.
  NOTE: this requires a database update. New update.php function included.
- Fixed important bug where category_menu generated menu links were never
  getting saved properly on insert, only on update. Needed to call
  category_get_parents() (from _category_menu_map_save_category()) with
  reset parameter set to TRUE, to clear a static var cache.
- category_display TOC listings are now working correctly. Yay! Introduced a
  new _category_menu_tree_all_data() function to make this possible. TOC
  depth is now being honoured, and all paths of the tree are being traversed
  to the specified depth. _category_menu_tree_all_data() is a modification of
  menu_tree_all_data(), and it maintains its own cache (which is cleared when
  saving affected categories/containers).

its distant-parent querying. Assigned nodes are designed such that
thousands of them have the exact same category as their menu parent. Including
them in the querying, in such cases, leads to PHP memory depletion and fatal
crashing.

- Upgrade path done for category, category_display, and category_menu.

now working much better.

with category_menu.

to be finished off and tested.

top-level ancestor is a hidden container with a custom menu parent set.
- Category_menu now sets breadcrumbs based on menu path, for all times where
node->category_menu_map['mlid'] is set.

- Got the book wrapper working: it now properly maintains the book table
(if category_menu-generated menu links are available, that is), and it
generates a nav block for each container.

  tagged node links.
- Fixed node IDs not getting outputted in tagged node link hrefs.
- Fixed (admin) titles not getting outputted on distant parent selection list.
- Fixed many bugs in the new category_menu menulink create / update logic.
- Added menu link deletion implementation to category_menu.
- Removed old D5 code from category_menu.
- Added a new 'menu wrapper' module. This is not a proper wrapper: it's
  exactly the same as the core D6 menu module, except that menu-on-the-fly
  functionality (i.e. the menu_nodeapi() and menu_form_alter() functions) has
  been stripped out, as menu OTF interferes with category_menu, and as it
  doesn't seem to be going away (or being made turn-off-able) any time soon.

- Added what I've got so far for the D6 category_menu module: mainly the container add/edit UI is done so far (lots of new AJAXy goodness), menu logic not yet implemented.
- Fixed up the too-strict line wrapping in the category.module code.

#279784 by etzel: variable_get() call missing default argument. Also started de-linebreaking category.module code.

'update' form buttons before calling category_node_save(), or before calling
taxonomy_node_save() for the wrapper.
- Updated category_del_container() to remove container IDs from
'category_allowed_containers_[nodetype]' variables on delete.
- Fixed incorrect logic in category_check_container_hierarchy().
- Changed the parent select form element, so that it doesn't appear for
free-tagging categories, and the user is instead given a message saying that
free-tagging categories always have their container set as their parent.
- Fixed a bug in wrapper's taxonomy_node_save() function - assigned category
objects not getting converted to terms.