A step closer to working like standard accounting programs where you click
an account to see transactions "in" that account. acct:PAT (or just PAT)
now matches the other postings in transactions matching the account
pattern, like ledger --related. When matching an account (or several) this
way, the unmatched accounts are dimmed to clarify what's happening.
Still to do: fix the sign of the running total, and find out how this
style of search will really coexist with the other ways of searching.
