make compilable on server

This version *does* compile on the server (and uses the newer `bytestring` library if available).

It does not *work* on the server, and the reason is the one identified by some of you: For no good cause, the executable takes the `Development` options from `settings.yml` instead of the `Production` options. Indeed, if one deletes the `Development` section from `settings.yml`, the executable complains about that. It shouldn't, because when compiled in non-development mode, it is very clearly told to use the `Production` settings. I'm baffled.