Processors can be initialized twice

[kstaken]

In the slicer and worker the calls to job_runner.initialize() can occur twice which has the side effect of calling newReader() twice on the loader operations. This can cause problems if the reader does initialization in that function and the Kafka reader can end up creating two client instances in the same worker process. This needs to be refactored to guarantee that job_runner.initialize() is called once and only once.