producer/consumer test of detached signatures in text-mode with \r line endings

I'd like to see each implementation make a signature over a one-octet file containing \r in text mode, and see which implementations can verify it.

This is similar to the one\rtwo\rthree sample in the linebreak normalization test, but handles producing and consuming as well.

I think there are not just two categories of normalization for this pathological message text, but i haven't been able to characterize all three categories yet. See also gosop #48.