Incoming Invoices (AP)

Record an invoice received from a supplier.

This will facilitate true AP functionality by separating the receipt of the invoice from the payment. Invoices should be able to linked to purchase orders, with modified amounts just like the bill payment. Bill payment should be modified to hook up with the invoices instead of the purchase orders, though a "quick-create" feature should still enable them (the invoice and the payment) to entered at the same time.

When amounts are modified, the AP, expense, and tax situations should reflect the modified amounts, leaving the purchase order amounts out of the ledger entirely. This may be analogous to the current situation with Bill Payment -- check first