2002-02-23  Andreas J. Guelzow <aguelzow@taliesin.ca>

	* cell-sort.glade : Add `add' entry
	* dialog-cell-sort.c (append_data) : code extracted from
	  load_model_data
	(load_model_data) : use append_data
	(value_to_global_range) : utility for cb_update_add_sensitivity
	(cb_update_add_sensitivity) : update add button sensitivity
	(cb_update_sensitivity) : call cb_update_add_sensitivity
	(cb_ok_clicked) : adjust base (the tree widget now stores
	  row and col numbers rather than offset)
	(cb_add_clicked) : new
	(dialog_init) : set up add-entry