By reverting django.core.signing to Django 1.11.8 version Django-Q works
This is not designed as a 'good' solution just to show where I think the
problem is.
* package signing protocol is now set to highest. Tests show this to be about a 35% speed increase and there is increased probability of correctly pickling complex objects.
* also upped the protocol on the result database picklefield.
* added a synchronous cluster simulation
* added a test for the sync function
* moved signing into its own module
* refactored imports to solve circular import problems stemming from the task module pretending to be a cluster
* added documentation for the new sync option