* lisp/icomplete.el: Change separator; add ido-style commands.

* lisp/icomplete.el: Change separator; add ido-style commands.
(icomplete-show-key-bindings): Remove custom var.
(icomplete-get-keys): Remove function.
(icomplete-forward-completions, icomplete-backward-completions):
New commands.
(icomplete-minibuffer-map): New var.
(icomplete-minibuffer-setup): Use it.
(icomplete-exhibit): Don't delay if the list of completions is known.
(icomplete-separator): New custom.
(icomplete-completions): Use it.
* lisp/minibuffer.el (completion-all-sorted-completions): Delete duplicates.
(minibuffer-force-complete-and-exit): New command.
(minibuffer--complete-and-exit): New function extracted from
minibuffer-complete-and-exit.
(minibuffer-complete-and-exit): Use it.