I would prefer to use the --json flag to provide syntactic sugar for setting the content type and accepts headers and leave the marshaling of data to a separate

I would prefer to use the --json flag to provide syntactic sugar for setting the content type and accepts headers and leave the marshaling of data to a separate tool. Or if it has to be baked in, refactor `jo` into `libjo` and a CLI wrapper so that the two tools behave the same way.