(tmm-old-mb-map): Initialize to nil.

(tmm-old-mb-map): Initialize to nil.
(tmm-delete-map): Don't use tmm-old-mb-map if nil.
(tmm-add-prompt): Bind C-n and C-p.
Put only the shortcuts into the completion buffer's map.
Produce the completion list by hand so as not to sort it.
(tmm-prompt): Start at the first item in the menu.
Don't reverse tmm-km-list; reverse compl-list instead.
Use try-completion in last-ditch attempt to find a match.
Rename compl-list to history.
(tmm-get-keybind): Put more local bindings last in a menu.
Major rewrite.
(tmm-menubar): Handle menu-bar-final-items.
(tmm-remove-shortcuts): Function deleted.
(tmm-add-shortcuts): If we can't find a letter shortcut,
use a numeric shortcut.