Refs #26536.

Thanks Sylvain Fankhauser for the very detailed report.

Calling conditional_escape() on SafeData won't change it.

Thanks to Andriy Sokolovskiy for initial patch.

Useful for overriding the DateTimeField widget.

The WGS84 proj string can differ depending on installed libs.
Refs #26592.

Thanks Michael Bitzi for the reporti and Tim Graham for the review.

On Python 3, sending emails failed for addresses containing non-ASCII
characters due to the usage of the legacy Python email.utils.formataddr()
function. This is fixed by using the proper Address object on Python 3.

The docs say that these headers always appear without the HTTP_ prefix.
This may have been an oversight when they were added in
d725cc97, the only commit that uses
these names.

Thanks Tim Graham for the review.

Thanks Tim Graham for completing the initial patch.

Didn't touch comments where it wasn't obvious that the code adhered to
the newer standard.

Thanks Maxime Lorant for the report and Anssi for the suggestion.

It's no longer necessary for GenericForeignKey (and any other virtual fields)
to intercept the field's values using the pre_init signal.