reportq from the ReportSpec, rather than being supplied as a separate
option.
This is the same approach used by the other reports, e.g. EntryReport,
PostingReport, MultiBalanceReport. This reduces code duplication, as
previously the reportq had to be separately tweaked in each of 5
different places.
If you call accountTransactionreport, there is no need to separately
derive the report query.
dropped journalPrices
renamed Price to AmountPrice, AKA "transaction price"
renamed MarketPrice to PriceDirective.
added new MarketPrice (more pure form of PriceDirective without the amount style information)
Prices is now a more efficient data structure, but not used yet.
