Expose Chain.spend_currency, Chain.balance_currency, and Chain.currency_supply, compiling to the new FATE opcodes. Auth.tx inspection gains AccountCreateTx, MintTx, ExchangeTx, SpendCurrenciesTx, and BurnTx. Pin gmbytecode to c44313e.
The arities field of the Chain.base_tx constructor is 22 integers long... This isn't very pretty but that is the design we've chosen.