(uniquify-rationalize): New fun. Store the fix-list in uniquify-managed.

(uniquify-rationalize): New fun.  Store the fix-list in uniquify-managed.
(uniquify-rationalize-file-buffer-names): Use it and make the args
non-optional (i.e. don't support "re-rationalize all" any more).
(uniquify-rerationalize-w/o-cb): New fun.
(uniquify-maybe-rerationalize-w/o-cb): Use it to rerationalize
immediately and only the relevant buffers.
Merged from uniquify-delay-rationalize-file-buffer-names and
uniquify-delayed-rationalize-file-buffer-names.
(kill-buffer-hook, rename-buffer): Use it.