2006-10-11  Morten Welinder  <terra@gnome.org>

	* src/xml-sax-write.c (cb_write_cell, xml_write_cells): Only last
	change.  The explicit ordering was useful.

	* src/expr.c (gnm_expr_hash): Renamed from ets_hash and adapted to
	traverse the entire tree.
	(gnm_expr_top_hash): New function.
	(gnm_expr_sharer_new): Use gnm_expr_top_hash, not ets_hash.
	(gnm_expr_sharer_share): Re-implement sharing.
	(gnm_expr_top_equal): If we have different hash values,
	short-circuit as false.