Redesign redisplay interface to drop global output_cursor.

Redesign redisplay interface to drop global output_cursor.
* dispextern.h (struct redisplay_interface): Remove cursor_to member.
(toplevel): Remove declaration of output_cursor.
(set_output_cursor, x_cursor_to): Remove prototype.
* window.h (struct window): New member output_cursor.
(output_cursor_to): New function to replace RIF member.
* dispnew.c (redraw_overlapped_rows, update_marginal_area)
(update_text_area, set_window_cursor_after_update): Use it.
* xdisp.c (output_cursor, set_output_cursor, x_cursor_to): Remove.
(x_write_glyphs, x_insert_glyphs, x_clear_end_of_line):
* nsterm.m (ns_update_window_begin, ns_update_window_end):
* w32term.c (x_update_window_begin, x_update_window_end):
* xterm.c (x_update_window_begin, x_update_window_end):
Adjust to use per-window output cursor.