gfio: improve option edit

Allow grouping of options into both categories, and groups. The
groups are within a category. This shrinks down the number of
job edit tabs a lot.

Work in progress...

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/engines/libaio.c b/engines/libaio.c
index 6bbd363..2b8c6da 100644
--- a/engines/libaio.c
+++ b/engines/libaio.c
@@ -32,10 +32,11 @@
 static struct fio_option options[] = {
 	{
 		.name	= "userspace_reap",
+		.lname	= "Libaio userspace reaping",
 		.type	= FIO_OPT_STR_SET,
 		.off1	= offsetof(struct libaio_options, userspace_reap),
 		.help	= "Use alternative user-space reap implementation",
-		.category = FIO_OPT_G_IO_ENG,
+		.category = FIO_OPT_C_IO,
 	},
 	{
 		.name	= NULL,