Algorithm::Accounting provide simple aggregation method to make log
accounting easier. It accepts data in rows, each rows can have many
fields, and each field is a scalar or a list(arrayref).

The basic usage is you walk through all your logs, and use append_data()
to insert each rows, (you'll have to split the line into fields), and
then call result() to retrieve the result, or report() to immediately
see simple result.

You may specify a filed_groups parameter (arrayref of arrayref), and
Algorithm::Accounting will account these fields in groups.