[feature request] IO-independent output

[nedpals]

Is your feature request related to a problem? Please describe. Currently it only supports outputting to os.Stdout.

Describe the solution you'd like Should take advantage of Go's io.Writer and have Stdout-specific configurations as a io.Writer-compliant type/struct. That way we can do stuff like simultaneous logging and displaying of output with io.MultiWriter

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context See the io package.