First stab at cache management backend. Everything seems to have been tested and working so far, but a number of things require a more specialized cache and can't go through the framework (e.g. user ranks which use references to map usernames to user IDs)
dd659f6ba891
Converting all tables on new installations to UTF-8; this may break MySQL 4.0 compatibility; several minor cosmetic fixes; set Powered button under Links to "on" by default
