Remove tui_list

Remove tui_list

This removes the tui_list type in favor of a std::vector.

gdb/ChangeLog
2019-06-25  Tom Tromey  <tom@tromey.com>

	* tui/tui-winsource.c (tui_display_main)
	(tui_update_source_windows_with_addr)
	(tui_update_all_breakpoint_info): Update.
	* tui/tui-win.c (tui_resize_all, tui_adjust_win_heights)
	(new_height_ok, parse_scrolling_args): Update.
	* tui/tui-stack.c (tui_show_frame_info): Update.
	* tui/tui-data.h (struct tui_list): Remove.
	(tui_source_windows): Return a reference to a std::vector.
	* tui/tui-data.c (source_windows): Now a std::vector.
	(tui_source_windows): Change return type.
	(tui_clear_source_windows): Rewrite.
	(tui_clear_source_windows_detail, tui_add_to_source_windows)
	(tui_free_all_source_wins_content): Rewrite.