2001-03-26  Morten Welinder  <terra@diku.dk>

	* src/workbook.c (workbook_cells): New function, extracted from
 	cmd_search_replace_do.

	* src/sheet.c (sheet_cells): New function, extracted from
 	cmd_search_replace_do.

	* src/cell.c (cell_has_comment_pos): New function for those cells
 	that aren't really there.

	* src/commands.c (cmd_search_replace_do): Use workbook_cells and
 	sheet_cells.
	(cmd_search_replace_do_cell): Change to take position instead of
 	cell.  Handle missing cells without crashing.