ginkgoctl command should block until service is "ready"

[chadselph]

It would be great for gingkoctl to provide a command that asked a service if it was ready.

The reasoning behind this is for startup scripts that use ginkgo start. Since the process backgrounds itself, it will return whether or not the service came up cleanly. The command should either return when it gets a response from the service, timeout, or notice that the service's pid is no longer running.

[progrium]

Seems like a lot of daemons do this, like apache. Wonder how they do it.