Start the pool of threads.

def start(self):
        """Start the pool of threads."""
        for i in range(self.min):
            self._threads.append(WorkerThread(self.server))
        for worker in self._threads:
            worker.setName("CP Server " + worker.getName())
            worker.start()
        for worker in self._threads:
            while not worker.ready:
                time.sleep(.1)