InvoiceShelf trusts client-supplied document totals

InvoiceShelf is an open-source web & mobile app that helps track expenses, payments and create professional invoices and estimates. Prior to version 2.4.0, InvoiceShelf invoice, estimate, and recurring-invoice creation paths accept client-supplied total, sub_total, tax, discount_val, and due_amount values without verifying that they match the submitted line items. An authenticated user can persist manipulated financial totals through InvoicesRequest::getInvoicePayload and the corresponding EstimatesRequest and RecurringInvoiceRequest handlers, causing stored document totals to disagree with their item prices and quantities. This issue is fixed in version 2.4.0.