Unable to set multiple OUs in the "names" field

x.509 allows for multiple OU fields, so that certificate ownership can be clearly identified even in very large organizations. It's common to see something like this in the Subject Name:

O="Company", OU="Engineering", OU="Operations", OU="Security"

CFSSL does not support this, which may surprise people who are used to this practice with x.509 certificates. Specifying the OU multiple times[1] silently ignores all but the last value. Specifying an array fails.

If it's possible to handle an array for the OU, that would be great. If not, having an alternative parameter that does accept an array ("OUs"?) would also be fine. If this isn't going to be implemented any time soon, printing a warning about multiple OUs being ignored would be nice, so people understand why they're not getting back the certificate they expect.

[1] https://coreos.com/os/docs/latest/generate-self-signed-certificates.html