Thanks Julian Wachholz for the report.

This also updates all dependent functionality, including modelform_factory
 and modelformset_factory, and the generic views `ModelFormMixin`,
 `CreateView` and `UpdateView` which gain a new `fields` attribute.

connection.ops.spatial_version is None for some backends (eg. MySQL) and
the comparison fails on Python 3 with TypeError.

Remove unnecessary check on __set__ parameters.

Refs #19445

This test hits a bug in current ports of MySQLdb.

Current ports of MySQLdb are very buggy in this area.

Made a few minor compatibility adjustments.

Some tests failed when the time zone definitions were loaded in MySQL
and pytz wasn't installed. This setup isn't supported.

Thanks n0nam3 for the patch.

Handle the `UnicodeDecodeError` exception, send a warning to `stdout` with the
file name and location, and continue processing other files.

Thanks vlad.london.uk@ for the report.

Thanks monuszko for the report.