The --format option's OutputFormat type was named confusingly like the
--output-format option. It has been renamed StringFormat to distinguish
it from StorageFormat (aka the data file format, referenced by
--output-format). Related code and types have been consolidated.
Also the (single-column) balance report's item rendering has had
some cleanup.
Here are hpack package.yaml files for the other hledger cabal files.
These remove a lot of human-error-prone duplication.
They are not used yet as hpack isn't quite mature enough -
when it supports flags and benchmarks we will probably switch.
