Added commodity_t::default_commodity.  Initialize the same.
Added commodity_t::default_commodity.  Initialize the same.

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