Changes include:
- flat mode now shows exclusive (subaccount-excluding) balances.
This is a deviation from ledger, but seems simpler and clearer
for users and implementors across the various modes.
- in flat mode, --depth now aggregates deeper accounts at the
depth limit, rather than just excluding them from the report.
This is more useful.
- in flat mode, --empty no longer shows parent accounts with
no postings.
- more tests, more debug output, clearer code
Two new multi-column balance report modes show ending balance per
period: `--cumulative`, starting from 0, and `--historical`, starting
from the historical starting balance.
The balance command's specification has been clarified and consolidated
in the Balance.hs haddock. Reports.hs has also had haddock updates. The
old AccountsReport type is now BalanceReport, still used by
single-column balance report. The new MultiBalanceReport type is used by
the multi-column reports.
