[project @ 2005-10-09 14:17:41 by ajt]
restructure User.pm (deal with perl objects by preference instead
of a usertag hash) and add support for user categories.
darcs changelog:
* first pass refactoring of User.pm
* make locking functional
* add support for unknown stanzas, and first pass at reading usercategories
* fix writing of unknown stanzas with multiline fields
* deal with multiline fields that don't have a summary line
* remove categories-by-cookie support, restructure category handling for
proper user-categories
* convert from add_usertags to add_user syntax
* cope with new user ids
* drop support for Prefix in the user files
* add support for recording categories
* finish off support for usercategory command
* finish adding support for user categories