This is a bug fix for the CLI's displayed fiat trade cost
value, which should be trade.volume, not offer.volume.  Offer volume
varies with BTC volatility, and the CLI should be showing the trade.volume
value instead, frozen when the contract is made.

This is a bug fix for the CLI's displayed altcoin trade amount
value, which should be trade.volume, not offer.volume.  It has been
hidden by the stability of the BSQ price, and exposed while testing
API support for XMR trades.

Fixes problem simlar to other CLI output changes in this PR.
CLI's 'gettrade' output should show contracted trade.price instead of
moving offer.price value for price margin based altcoin offers.

This fixed bug did not affect any fiat or BSQ trades, only price margin
based XMR trades, and API support for XMR trading has not yet been
released.