modifyshelfcontents-
if this script has to modify the shelf content.
shelfnumber-
to know on which shelf this script has to work.
addbarcode-
op-
op can equal the following values:
* 'modifsave' to save changes on the shelves
* 'modif' to change the template to allow modification of the shelves.
viewshelf-
to load the template with 'viewshelves param' which allows reading the shelves information.
shelves-
if == 1, then call the function shelves to add or delete a shelf.
addshelf-
if the param shelves == 1, then addshelf must be equals to the name of the shelf to add.