Implement a more dynamic celery queue system

* Meant to be a starting point to more efficiently manage work routing
  and to balance work across all tower nodes
* Integrate flower as a dev tool that starts alongside other nodes.
  Helpful for observing and monitoring the queues/exchanges
* For the moment, force the task manager to only run on one node (not
  sure if this is needed)
* Define queues and routes for all task work
* Bump celery version to 3.1.23
* Expose flower through haproxy

tools/docker-compose.yml

@@ -12,6 +12,7 @@ services:
     ports:
       - "8080:8080"
       - "8013:8013"
+      - "5555:5555"
     links:
       - postgres
       - memcached