2005-06-08  Morten Welinder  <terra@gnome.org>

	* src/sheet.c (gnm_sheet_class_init): Rename "visible" property to
	"visibility" and make it an enum.  All users changed.
	* src/sheet.h (struct _Sheet): Ditto for is_visible member.

	* src/workbook-view.c (wb_view_sheet_remove): New function to
	mirror wb_view_sheet_add.
	* src/workbook.c (workbook_sheet_hide_controls): Use
	wb_view_sheet_remove.