* calendar/todos.el (todos-ignore-archived-categories):

* calendar/todos.el (todos-ignore-archived-categories):
Revert last change; remove :initialize and :set functions; change
use and change users accordingly.
(todos-reset-categories, todos-categories-full)
(todos-truncate-categories-list): Remove.
(todos-set-categories, todos-update-categories-sexp):
Use todos-categories instead of todos-categories-full; remove use
of todos-ignore-archived-categories and
todos-truncate-categories-list.
(todos-check-format, todos-repair-categories-sexp):
Use todos-categories instead of todos-categories-full.
(todos-read-category): Improve last change.
(todos-validate-name): Use completing-read.
(todos-categories-category-number): Rename from
todos-category-number and adjust users.
(todos-update-categories-display, todos-mode-external-set)
(todos-delete-category, todos-move-category, todos-merge-category)
(todos-unarchive-items): Remove use of todos-categories-full and
todos-ignore-archived-categories.
(todos-modes-set-3, todos-add-category): Remove use of
todos-categories-full.
(todos-edit-mode): Fix typo.
(todos-forward-category): Use todos-ignore-archived-categories.