Remove make_delete_ui_cleanup

Remove make_delete_ui_cleanup

This removes new_ui and delete_ui in favor of ordinary 'new' and
'delete', and then removes make_delete_ui_cleanup in favor of
std::unique_ptr.

2017-10-03  Tom Tromey  <tom@tromey.com>

	* event-top.c (stdin_event_handler): Update.
	* main.c (captured_main_1): Update.
	* top.h (make_delete_ui_cleanup): Remove.
	(struct ui): Add constructor and destructor.
	(new_ui, delete_ui): Remove.
	* top.c (make_delete_ui_cleanup): Remove.
	(new_ui_command): Use std::unique_ptr.
	(delete_ui_cleanup): Remove.
	(ui::ui): Rename from new_ui.  Update.
	(free_ui): Remove.
	(ui::~ui): Rename from delete_ui.  Update.