Added relationshio from InvoiceJournal to Invoice
Added Journal subclasses (HubFeeInvoiceJournal, SellerHubFeeInvoiceJournal, HubHubFeeInvoiceJournal)
Added Journal subclasses (HubFeeInvoiceJournal, SellerHubFeeInvoiceJournal, HubHubFeeInvoiceJournal)