celery: replace loader.PylonsSettingsProxy with a simple configuration object The proxy was quite complex and did all the conversion at runtime, making it hard to figure out exactly what it was doing. Instead, just create a simple configuration object as described on http://docs.celeryproject.org/en/3.1/userguide/application.html and convert all relevant config settings up front. We don't convert all config settings, but only the ones Celery seems to be interested in. The value conversion heuristics are the same as before and still seem quite fragile.