'new_group' option

By default, jobs in a file are part of the same reporting group
unless seperated by a stone wall or if they define a group by
themselves (numjobs=x is used). Inserting a 'new_group' parameter
in a job description, will mark the start of a new reporting group.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fio.h b/fio.h
index bd78e85..a2be6d5 100644
--- a/fio.h
+++ b/fio.h
@@ -368,6 +368,7 @@
 	enum fio_memtype mem_type;
 
 	unsigned int stonewall;
+	unsigned int new_group;
 	unsigned int numjobs;
 	os_cpu_mask_t cpumask;
 	unsigned int iolog;