run Go programs as a service on major platforms

 Service will install / un-install, start / stop, and run a program as a
 service (daemon). Currently supports:
 .
  * Windows XP+,
  * Linux with systemd, Upstart, SysV, and
  * OSX with launchd.
 .
 Windows controls services by setting up callbacks that are non-trivial. This
 is very different than other systems. This package provides the same API
 despite the substantial differences. It also can be used to detect how a
 program is called, from an interactive terminal or from a service manager.