add launchcfg and rename launchctl to launchadm

[mheily]

introduce a notification system, with a CLI tool named launchcfg.

To avoid naming confusion, rename launchctl to launchadm. It is now a tool for administering launchd itself, where launchcfg takes a bigger role in enabling/disabling/configuring jobs.

[mheily]

Instead of renaming, keep the two tools separate.

• launchctl: manage launchd itself (stop, start, load jobs)
• launchadm: manage a single job running under launchd (stop, start, status, configure)

Examples:

• Run launchctl shutdown to cleanly terminate launchd
• Run launchadm httpd restart to restart Apache

[mheily]

jobcfg solves this, mostly.