Thanks Seth Gottlieb for help with the documentation and
Carl Meyer and Joshua Kehn for reviews.

Remove unnecessarily rude terminology.

This makes it much easier to diagnose a test failure when all
you have is the stack trace from an uncaught TemplateSyntaxError.

It didn't work anymore since the commit that enabled test
parallelization by default because parallel was equal to 0
at that point.

Since --parallel is documented not to work on Windows, it's better to
ignore it and run without parallelization than to crash. For example
this could simplify cross-platform test scripts.

As discussed on the ticket, this isn't a pattern we should recommend.

This reverts commit 47016d43.

Partial forwardport of 3cc5cc79 from
stable/1.8.x as the issue was already fixed in master in
a7bc00e1

This allows dynamically-generated attributes to be specified in
checked ModelAdmin attributes without triggering errors.

Düsseldorf now appears as Dusseldorf in the latest version
of the GeoIP2 database.