Remove `Runner.run` and `ServiceHandler.run`

This removes the `Runner.run` and the `ServiceHandler.run` class
methods. These were a neat feature but haven't really worked out
or been used. Since these haven't been used, this removes them so
they no longer have to be maintained. With planned changes to the
`Runner.new` args, this avoids having to update both of these
methods to using the new args.
Merge pull request #122 from redding/jcr-remove-runner-handler-class-methods

Remove `Runner.run` and `ServiceHandler.run`
Add `ProcessSignal` for sending signals to a Sanford process

This adds logic for sending signals to a Sanford process. This
will be used by the CLI to stop, halt or restart a Sanford
process. It will try and find an existing PID file for the process
and send the signal to the PID stored in it. This replaces logic
that currently exists in the `Manager`.