[CONTRIB] halog: report per-url counts, errors and times

Using -u{,c,e,t,a,to,ao} it is possible to get per-URL statistics, sorted by
URL, request count, error count, total time, avg time, total time on OK requests,
avg time on OK requests.

Since it has to parse URLs and store a number of fields, it's quite slower
than other methods, but still correct for production usage (typically 800000
lines or 270 MB per second on a 2 GHz system).

Results are sorted in reverse order so that it's easy to catch them by piping
the output to the "head" command.
(cherry picked from commit 15ce7f56d15f839ce824279b84ffe14c58e41fda)
2 files changed