Revert: MongoQuery order_by with properties in dict field

Python 3.9 support - bugs

Python 3.9 support

Version 0.6.1

Forced the 10000 hard-limit on all count()

Changed version number from 0.4.0.bigml-2 to 0.4.0.bigml-3

Version 0.4.0.bigml-2

Version 0.4.0.bigml-1

Version 0.4.0-bigml-2

0.4 is ready!

Fix: Make it possible to store empty documents. Backport of 7843a fro…

…m master. Closes django-nonrel#41.