Jobboard example that show jobs + workers + producers

Add a new example that spins up a set of threads to simulate
the actual workers and producers that would be normally attached
to a jobboard and use these threads to producer and consume a
set of simple jobs (that are filtered on by the workers).

- This also fixes how python3 removed the __cmp__ operator which
  we were using for sorting the jobs that were posted and now we
  must use __lt__ instead.

Fixes bug 1367496

Part of blueprint more-examples

Change-Id: Ib8d116637b8edae31e4c8927a28515907855f8bf
Merge "Jobboard example that show jobs + workers + producers"