(IT_set_face): Rewritten for the new redisplay engine.

(IT_set_face): Rewritten for the new redisplay engine.
Use default frame colors if the face doesn't specify them; invert
the colors if highlight is ON.
(IT_write_glyphs): Rewritten for the new redisplay engine.
(IT_change_line_highlight): Add (unused) parameter Y, since that's
how the hook is called by term.c.
(IT_copy_glyphs): New function, copies an area of the display in
video RAM.
(IT_insert_glyphs): Rewritten to DTRT instead of aborting, since
redisplay now calls it even if char_ins_del_ok is zero.
(IT_set_frame_parameters): Prototype changed.  Calls the new
load_color.  Puts the new fore/background colors into the default
face on current frame.
(IT_menu_display): Rewritten to handle the new struct glyph
instead of a char array.
(XMenuActivate): Call lookup_derived_face to create and use
special faces for the pop-up and drop-down menus.