How to Gracefully Restart A Parent Process

When enabling or disabling plugins in Tanzawa, for urls to register correctly across all sub-processes, you must restart all processes, not just fiddle with the process that made the request.

The complete changes are in PR #121, but the line of interest is below.

import os
import signal

os.kill(os.getppid(), signal.SIGHUP)

Where getppid gets the process id of the parent process (gunicorn, uwsgi, etc...) and sends it a HUP signal.