?? Allow -S /dev/md? - current complains subsequent not a/d/r
+* new "Query" mode to subsume --detail and --examine.
+ --query or -Q, takes a device and tells if it is an MD device,
+ and also tells in a raid superblock is found.
+
* write proc.c to parse /proc/mdstat file, and maybe /proc/partitions too.
Build list of arrays: name, rebuild-percent