This updates various miscellaneous pieces of code that were only

compatible with Python 2.7 and/or Django 1.6, making them compatible

with Python 3.x and Django 1.11.
There's fixes for importing of modules, string encodings, type checks,

generators vs. lists, Unicode characters in tests, model form

definitions, error messages that differed across versions, and other

small changes.

Unit tests pass on Python 2.7/Django 1.6 and Python 3.7/Django 1.11

(with other in-progress changes).