Clean dead code

dev/skeletons/skeleton_class.class.php

htdocs/compta/paiement/class/cpaiement.class.php

htdocs/compta/sociales/class/cchargesociales.class.php

htdocs/ecm/class/ecmfiles.class.php

htdocs/fourn/class/fournisseur.commande.dispatch.class.php

htdocs/install/mysql/tables/llx_website_pages.sql

htdocs/product/stock/class/productlot.class.php

htdocs/product/stock/class/productstockentrepot.class.php

htdocs/websites/class/website.class.php

htdocs/websites/class/websitepage.class.php