Work on inventory module debug

htdocs/admin/stock.php

htdocs/core/class/commonobject.class.php

htdocs/core/class/coreobject.class.php

htdocs/core/menus/standard/eldy.lib.php

htdocs/core/modules/modStock.class.php

htdocs/install/mysql/tables/llx_fichinter.sql

htdocs/install/mysql/tables/llx_inventory.sql

htdocs/product/inventory/card.php

htdocs/product/inventory/class/inventory.class.php

htdocs/product/inventory/tpl/inventory.tpl.php