* xselect.c (Qcut_buffer0): Symbol removed; we're using a new

* xselect.c (Qcut_buffer0): Symbol removed; we're using a new
	interface to the cut buffer now.
	(NUM_CUT_BUFFERS, cut_buffer_atom, cut_buffer_value,
	cut_buffer_cached, cut_buffer_just_set): New variables.
	(Fx_own_selection, Fx_selection_value): Dike out the code to
	handle CUT_BUFFER0 requests.
	(Fx_get_cut_buffer, Fx_set_cut_buffer, x_watch_cut_buffer_cache,
	x_invalidate_cut_buffer_cache): New functions.
	(syms_of_xselect): Don't bother to initialize Qcut_buffer0.
	Initialize and staticpro cut_buffer_value, and defsubr
	Sx_get_cut_buffer and Sx_set_cut_buffer.
	* xterm.c (XTread_socket): Pass PropertyNotify events from the
	root window to x_invalidate_cut_buffer_cache.
	(x_term_init): Call x_watch_cut_buffer_cache here.