Add hidden option MAIN_USE_BACKGROUND_ON_PDF

htdocs/includes/modules/action/rapport.pdf.php

htdocs/includes/modules/commande/pdf_edison.modules.php

htdocs/includes/modules/commande/pdf_einstein.modules.php

...s/modules/expedition/pdf/pdf_expedition_merou.modules.php

.../modules/expedition/pdf/pdf_expedition_rouget.modules.php

htdocs/includes/modules/facture/pdf_crabe.modules.php

htdocs/includes/modules/facture/pdf_oursin.modules.php

...cs/includes/modules/livraison/pdf/pdf_sirocco.modules.php

htdocs/includes/modules/livraison/pdf/pdf_typhon.modules.php

htdocs/includes/modules/propale/pdf_propale_azur.modules.php

...cs/includes/modules/propale/pdf_propale_jaune.modules.php

htdocs/includes/modules/rapport/pdf_paiement.class.php

...ludes/modules/supplier_order/pdf/pdf_muscadet.modules.php

htdocs/lib/pdf.lib.php