The balance command's --format option (in single-column mode) can now
adjust the rendering of multi-line strings, such as amounts with multiple
commodities. To control this, begin the format string with one of:
%_ - renders on multiple lines, bottom-aligned (the default)
%^ - renders on multiple lines, top-aligned
%, - render on one line, comma-separated
Also the final total (and the line above it) now adapt themselves to a
custom format.
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.
