2011-01-09  Andreas J. Guelzow <aguelzow@pyrshep.ca>

	* src/sort.c (sort_compare_cells): add argument and use it to
	  decide whether to use the cacheing version of value_compare
	(sort_compare_sets): add argument and change all callers
	(gnm_sort_contents): if we are not in the default locale, do not cache
	  collation keys
	* src/value.h (value_compare_no_cache): new
	* src/value.c (value_compare_no_cache): new
	(value_compare_real): new
	(value_cmp): use value_compare_real
	(value_compare): use value_compare_real
	(gnm_string_cmp): new
	(gnm_string_cmp_ignorecase): new