Implemented drive role 3, sequential write-only stdio drives (e.g. stdout)

libburn/transport.h

@@ -121,7 +121,12 @@ struct burn_format_descr {
 /** Gets initialized in enumerate_common() and burn_drive_register() */
 struct burn_drive
 {
-	/* ts A70902: 0=null-emulation , 1=MMC drive , 2=stdio-emulation */
+	/* ts A70902:
+		0=null-emulation
+		1=MMC drive ,
+		2=stdio random read-write
+		3=stdio sequential write-only
+	*/
 	int drive_role;
 
 	int bus_no;