Sync STDOUT and STDERR for realtime heroku logging

Without this patch log entries from the worker process aren't displayed
until the worker is shut down.  This patch addresses the problem by
setting the STDERR and STDOUT file handles to synchronous mode as
documented at https://devcenter.heroku.com/articles/logging
Merge branch 'fix_dj_logging'

* fix_dj_logging:
  Sync STDOUT and STDERR for realtime heroku logging

closes: #13