Discussion with Jim Blandy reveals that it can no longer be made to work
properly at all due to changes in Emacs's terminal-control interface. So
it's getting deep-sixed, but these cleanups go in on the outside chance that
we want to revive it someday.
* vip.el (vip-escape-to-emacs, vip-prefix-arg-value,
vip-prefix-arg-com): Use unread-command-event instead of
unread-command-char; respect its new semantics.
* terminal.el (te-escape-extended-command-unread): Same.