Initial support of market value reporting and currency conversion,
similar in spirit to Ledger's. The balance command now has a -V/--value
flag that converts all the reported amounts using their "default market
price". That is the latest market price (P directive, formerly called
"historical prices") found in the journal for their commodity that is on
or before the report end date.
Unlike Ledger, hledger's -V only uses the market prices recorded with P
directives, ignoring transaction prices recorded as part of posting
amounts (which -B/--cost uses). Using -B and -V together is allowed.
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