Finish coding mouse highlight redesigned for portability.

Finish coding mouse highlight redesigned for portability.
Not compiled yet.

 nsterm.m (ns_update_window_begin, ns_update_window_end)
 (ns_update_end, x_destroy_window, ns_frame_up_to_date)
 (ns_dumpglyphs_box_or_relief, ns_maybe_dumpglyphs_background)
 (ns_dumpglyphs_image, ns_dumpglyphs_stretch)
 (ns_initialize_display_info, keyDown, mouseMoved, mouseExited):
 Replace Display_Info with Mouse_HLInfo everywhere where
 mouse_face_* members were accessed for mouse highlight purposes.
 xterm.c (x_update_window_begin, x_update_window_end)
 (x_update_end, XTframe_up_to_date, x_set_mouse_face_gc)
 (handle_one_xevent, x_free_frame_resources, x_term_init): Replace
 Display_Info with Mouse_HLInfo everywhere where mouse_face_*
 members were accessed for mouse highlight purposes.
 w32term.c (x_update_window_begin, x_update_window_end)
 (x_update_end, w32_read_socket, x_free_frame_resources)
 (w32_initialize_display_info): Replace Display_Info with
 Mouse_HLInfo everywhere where mouse_face_* members were accessed
 for mouse highlight purposes.
 xdisp.c (show_mouse_face, note_mode_line_or_margin_highlight)
 (note_mouse_highlight) [HAVE_WINDOW_SYSTEM]: Don't run GUI code
 unless the frame is on a window-system.