transaction prices.
When given --infer-costs, hledger will now separately infer transaction
prices for different prices. Given a pair of adjacent conversion
postings, hledger will check if there is a single posting with a
transaction price which matches both the amounts. If so, it associates
those conversion postings to that priced post.
If it can't find any transaction price postings which match, it will
find the first non-transaction price post which matches one of the two
amounts, and will add a transaction price to that, and associate them.
c54fb4d514