CONTRIB: halog: sort URLs by avg bytes_read or total bytes_read

The patch attached to this mail brings ability to sort URLs by
averaged bytes read and total bytes read in HALog tool.
In most cases, bytes read is also the object size.
The purpose of this patch is to know which URL consume the most
bandwith, in average or in total.
It may be interesting as well to know the standard deviation (ecart
type in french) for some counters (like bytes_read).

The results:
- Sorting by average bytes read per URL:
./halog -uba <~/tmp/haproxy.log | column -t | head
2246 lines in, 302 lines out, 194 parsing errors
18    0    5101     283    5101   283    126573  2278327  /lib/exe/js.php
1     0    1        1      1      1      106734  106734   /wp-admin/images/screenshots/theme-customizer.png
2     0    2        1      2      1      106511  213022   /wp-admin/css/wp-admin.css
1     0    1        1      1      1      96698   96698    /wp-admin/images/screenshots/captions-1.png
1     0    1        1      1      1      73165   73165    /wp-admin/images/screenshots/flex-header-1.png
4     0    0        0      0      0      64832   259328   /cuisine/wp-content/plugins/stats/open-flash-chart.swf
1     0    0        0      0      0      48647   48647    /wp-admin/images/screenshots/flex-header-3.png
1     0    0        0      0      0      44046   44046    /wp-admin/images/screenshots/captions-2.png
1     0    1        1      1      1      38830   38830    /wp-admin/images/screenshots/flex-header-2.png

- Sorting by total bytes read per URL:
./halog -ubt <~/tmp/haproxy.log | column -t | head
2246 lines in, 302 lines out, 194 parsing errors
18    0    5101     283    5101   283    126573  2278327  /lib/exe/js.php
60    0    14387    239    14387  239    10081   604865   /lib/exe/css.php
64    2    8820     137    8819   142    7742    495524   /doku.php
14    0    250      17     250    17     24045   336632   /wp-admin/load-scripts.php
71    0    6422     90     6422   90     4048    287419   /wp-admin/
4     0    0        0      0      0      64832   259328   /cuisine/wp-content/plugins/stats/open-flash-chart.swf
2     0    2        1      2      1      106511  213022   /wp-admin/css/wp-admin.css
31    3    5423     174    5040   180    6804    210931   /index
10    0    429      42     429    42     18009   180093   /cuisine/files/2011/10/tarte_figue_amande-e1318281546905-225x300.jpg
1 file changed