Preliminary Debian support

This is based the work in #6 by @saz.

Added a new init.d file for Debian, which requires the "daemon" package.
This will be automatically required on Debian systems.
I couldn't find any modules - it's a fairly simple package that has no options. If you'd rather not have the dependency the init file could probably be refactored to avoid using it.

Otherwise I'll make it use `ensure_packages`, add dependency ordering, and add a default case.