Make the rejester integration work correctly, and test it.

Pass the complete streamcorpus_pipeline configuration in the rejester
work_spec 'config' field (work_spec['config']['streamcorpus_pipeline'] should
exist).  For work items pass keys as the file names to process, and
values as dictionaries { 'start_chunk_time': 0 }.

The test runs a single test locally, though it does depend on an external
redis database for synchronization.
General streamcorpus_pipeline logging cleanup.

Remove streamcorpus_pipeline._logging, and use dblogger.configure_logging()
in the top-level entry point instead.  Be quieter about spitting out things
like the configuration during pipeline execution.
Make the spinn3r ingest a "reader" stage
Very minor logging touchups

Even with debug logging, don't log "yielding to gevent"; do debug log at least
once the actual configuration; notes on local file output