Writing to Stderr from an Encoder

[kevina]

Is the current model that if a command needs to write to both stdout and stderr than PostRun should be used?

If so this seams like an overkill for example in filestore verify non-fatal errors may be printed to stderr. By forcing this command to use a PostRun we lose the benefit of the Encoder.

CC @Stebalien @keks

[kevina]

This may be a duplicate of #115, or at least is closely related.

[Stebalien]

Yeah, it's basically the same issue. The current model is to just use a PostRun (ufnortunately).

[kevina]

@Stebalien thanks