stat_field.h defines the counter fields with name, type, (printf)format
and description.

stats.h defines a structure with these fields.

shmlog.h makes the structure  part of the shared memory logs header.

Implent the "stats" CLI word in the management process.



git-svn-id: http://www.varnish-cache.org/svn/trunk@243 d4fa192b-c00b-0410-8231-f00ffab90ce4