cardiff: Adding DETAIL log level

This log level will be used later to print details of some performance
items.
cardiff: Adding DETAIL mode

The DETAIL mode is a powerfull way to extract performances measures from
the original performance results.

To use it, you have to select a group, a category (like cpu, disk or
memory benchmarks) and an item (logical_1, sda, ..) to report.

The -g, -c and -i options provides the CLI control points for those
element. Not that it's possible to use regexp to select only a couple of
items like "-c 'standalone_rand.*_4k_IOps'" or "-i 'sd.*'" or both of
course.

A typical usage & output looks like:

[user@host]$ cardiff.py -p 'sample/*.hw_'  -l DETAIL -g '1' -c 'standalone_rand.*_4k_IOps' -i 'sd.*
[...]
Group 1 : Checking logical disks perf

standalone_randwrite_4k_IOps      : DETAIL  : sd.*
     CZ3404YWP2  CZ3404YWP4  CZ3404YWP6  CZ3404YWP8  CZ3404YWPA  CZ3404YWPC  CZ3404YWPE  CZ3404YWPH  CZ3404YWPK  CZ3404YWPM  CZ3404YWPP  CZ3404YWPS  CZ3404YWPV  CZ3404YWPX  CZ3404YWR0
sda         660         685         683         585         682         657         679         684         645         673         514         674         650         620         681
sdb         658         676         687         679         689         692         574         685         698         657        1562         645         607         588         687

standalone_randread_4k_IOps       : DETAIL  : sd.*
     CZ3404YWP2  CZ3404YWP4  CZ3404YWP6  CZ3404YWP8  CZ3404YWPA  CZ3404YWPC  CZ3404YWPE  CZ3404YWPH  CZ3404YWPK  CZ3404YWPM  CZ3404YWPP  CZ3404YWPS  CZ3404YWPV  CZ3404YWPX  CZ3404YWR0
sda         313         306         312         316         312         306         309         307         301         290         299         310         325         288         311
sdb         299         305         306         305         299         300         297         304         296         300         306         301         289         297         305

or

[user@host] : cardiff.py -p 'sample/*.hw_'  -l DETAIL -g '1' -c 'loops_per_sec' -i 'logical_1.*'
[...]
Group 1 : Checking CPU perf

loops_per_sec                     : DETAIL  : logical_1.*
            CZ3404YWP2  CZ3404YWP4  CZ3404YWP6  CZ3404YWP8  CZ3404YWPA  CZ3404YWPC  CZ3404YWPE  CZ3404YWPH  CZ3404YWPK  CZ3404YWPM  CZ3404YWPP  CZ3404YWPS  CZ3404YWPV  CZ3404YWPX  CZ3404YWR0
logical_1          454         454         452         454         450         452         455         452         454         452         450         458         454         451         454
logical_10         452         451         449         452         455         450         453         450         451         450         455         454         451         457         452
logical_11         453         452         450         453         456         450         454         450         482         450         457         455         452         458         453
logical_12         454         452         450         453         457         451         453         451         452         451         458         455         452         450         453
logical_13         454         453         451         454         450         452         454         452         453         452         449         457         453         450         454
logical_14         455         454         452         454         450         453         455         452         454         452         450         449         454         451         454
logical_15         455         454         453         455         451         453         455         453         454         453         451         450         454         452         455
logical_16         456         455         462         456         461         453         456         462         455         453         460         459         455         461         456
logical_17         449         457         454         449         453         454         449         454         457         454         452         451         457         453         449
logical_18         450         458         454         450         454         455         450         455         458         455         453         452         457         454         449
logical_19         451         450         456         451         454         457         451         455         450         457         454         453         449         454         451