Property Groups

Methods used to handle property groups:

Method	Description
sale.propertygroup.add	Adds property group.
sale.propertygroup.delete	Deletes property group.
sale.propertygroup.get	Accesses fields of property group.
sale.propertygroup.getFields	Returns fields of property group.
sale.propertygroup.list	Gets list of property group.
sale.propertygroup.update	Updates fields of property groups.