Fix: Preview feature

htdocs/comm/propal/apercu.php

htdocs/commande/apercu.php

htdocs/commande/fiche.php

htdocs/compta/facture/apercu.php

htdocs/compta/prelevement/bon.php

htdocs/core/class/html.formfile.class.php

htdocs/core/lib/company.lib.php

htdocs/core/lib/contract.lib.php

htdocs/core/lib/fichinter.lib.php

htdocs/core/lib/files.lib.php

htdocs/core/lib/fourn.lib.php

htdocs/core/lib/invoice.lib.php

htdocs/core/lib/order.lib.php

htdocs/core/lib/product.lib.php

htdocs/core/lib/project.lib.php

htdocs/core/lib/propal.lib.php

htdocs/core/lib/tax.lib.php

htdocs/fichinter/apercu.php