Add support to use the Django debug toolbar with an easy setting in
local_settings.py.

Closes: #174

templates/public/about: remove unsupported section

added docker section to /downloads

Some py3 fixes and some refactoring

Fix a typo in donor_import.py

Enable X-Content-Type-Options to prevent a browser from sniffing the
MIME type if the content type is not set. Enable cross site filter
protection supported by most browsers.

Instead of using a python module use the build-in mock and remove the
module from requirements.txt

MarkupSafe was last used in 353f803c, but obsolete since we now use
Django for making markup safe.

Switch to Django 2.x with Python 3.7

Add test cases for 404 and 404 variant url exceptions.

Two functions where called test_valid, rename one.

urllib2 has been renamed to urllib and the module layout is changed,
update the code to reflect these changes in Python 3

This reverts commit bb18fa33.

Update to the latest version for Python 3 compatibiity.

Frank Vanderham authored Apr 25, 2018 and Jelle van der Waa committed Jan 21, 2019

Revisited earlier commit where email subject lines with potentially
mixed encoding are joined into a single string. This fix brings in
the 'codecs' import to decode bytes to string using either the passed
encoding (if provided) or otherwise utf-8.

Changed the test_donor_import to no longer convert the Header to a
string and instead leave it as a byte array.

Frank Vanderham authored Apr 23, 2018 and Jelle van der Waa committed Jan 21, 2019

Under Python 3, the error message that is expected to be returned has
changed. This fixes the 'expected' error so that the test succeeds and
fails as required.

Frank Vanderham authored Apr 23, 2018 and Jelle van der Waa committed Jan 21, 2019

By reordering INSTALLED_APPS, a large amount of false positives that
were generated during automated tests are avoided. This is the stated
(and otherwise harmless) work-around as per the Django bug:
https://code.djangoproject.com/ticket/10827

Frank Vanderham authored Apr 23, 2018 and Jelle van der Waa committed Jan 21, 2019

* Fixed issue with string concatenation that fails under Python 3
* Fixed issue with concatenating strings with potentially mixed
encoding. All strings are now first converted to UTF-8 and then
concatenated.

Frank Vanderham authored Apr 23, 2018 and Jelle van der Waa committed Jan 21, 2019

In several places the README references python2, these have all been
replaced with python or python3, where applicable.