(ediff-make-control-frame): optimized for display.

(ediff-make-control-frame): optimized for display.
Commented out (redraw-display), to improve speed.

Got rid of toolbars in control frame in xemacs

Changed window-min-height from 1 to 2

(ediff-diff-at-point,ediff-toggle-multiframe): bug fixes.
(ediff-destroy-control-frame,ediff-window-display-p): new functions.

Converted xemacs *screen* nomenclature to *frame*.
Incorporated overlay strings. Ediff no longer runs under emacs
19.28 and earlier and XEmacs 19.11 and earlier.

Changed window-system to ediff-window-display.

(ediff-toggle-multiframe): fixed.
(ediff-destroy-control-frame): new function.