Give up and move sutureslog to its own project.

Fix the location of sutureslog.

Add a slog-based logger people can use without writing it themselves.

README.md updates for v4.0.2.

Add documentation for version 4.0.1.

Merge pull request #43 from thejerf/jcontext

Upgrade to suture 4.0.

Fix issue #35: Supervisor can't panic if stop is called before Serve.

In hindsight, that's obvious. The contract is that Stop can be called
before Serve, and the service ought to notice that and not start up
in that case. Supervisors are not excluded from this policy.

Fix #34: Calling .Stop on a supervisor while trying to shut down serv…

…ice will not lose service shutdown.

When the supervisor shut down, the main loop is stopped and we go into
a cleanup loop. That cleanup loop could not receive notifications
that services sucessfully shut down, so it would delay until the
timeout and report a failed shutdown.

Release v3.0.0.