Added missing casts to amount_t.
Added missing casts to amount_t.

jwakely/ledger,afh/ledger,jwakely/ledger,afh/ledger,duncanmortimer/ledger,ledger/ledger,jwakely/ledger,jwakely/ledger,afh/ledger,duncanmortimer/ledger,jwakely/ledger,ledger/ledger,paulbdavis/ledger,afh/ledger,duncanmortimer/ledger,duncanmortimer/ledger,afh/ledger,ledger/ledger,paulbdavis/ledger,ledger/ledger,duncanmortimer/ledger,paulbdavis/ledger,paulbdavis/ledger,ledger/ledger,duncanmortimer/ledger,paulbdavis/ledger,paulbdavis/ledger,jwakely/ledger,paulbdavis/ledger,duncanmortimer/ledger,jwakely/ledger