Ajout du <Prochaine livraison>
Finalisation de l'export au format texte
Remove main for DeliverySheet
Merge remote-tracking branch 'origin/feature/export' into develop

Conflicts:
	OptiFret/nbproject/build-impl.xml
	OptiFret/src/model/DeliverySheetModel.java
	OptiFret/test/test/DeliverySheetModelTest.java
Add export in controller, remove generated fixtures