- write a zc.buildout/grok quickstart
- would love a module-based API review of docs.

Improvements

- queues should be pluggable like agent with filter
- consider agent sort function for jobs to implement priority queues

More docs:

- show how to broadcast, maybe add conveniences

- show how to use with collapsing jobs (hint to future self: use external queue
  to put in work, and have job(s) just pull what they can see from queue)

- custom retry policies, particularly for non-transactional tasks;

- changing the default retry policy, per-process and per-agent; and

- changing the default log level for queue jobs, callback jobs, and per-job.
