(vip-envelop-ESC-key): if an ESC-sequence translates

(vip-envelop-ESC-key): if an ESC-sequence translates
into a function key, pretend that this key was the last command event.

(vip-put-back,vip-Put-back): now emulate Vi's behavior
more closely.

(vip-line): no longer not bombs out.
(vip-exec-shift) now preserves the point.

Fixed the behavior of the Vi commands M, L, G, yw, dg, etc.

Changed vip-*-frame-* to *-frame-*, incorporated overlay strings,
unread-command-events, removed support for emacs versions 19.28 and
xemacs 19.11 and earlier.