Add output_logger & error_logger support to supervise-daemon

[Higgs1]

Duplicate of Issue #644 for better visibility in "discussions". Please delete if not needed. I wrote up a PR in #653. Also addresses #341 and #118.

Please review and merge, or discuss, or request edits at your leisure. Thank you :D

[navi-desu]

the PR got merged a while ago, closing.