Use Orientation EXIF tag in photo to determine orientation on upload

Closes #591

See merge request thalia/concrexit!730

Fix RegistrationInformationfield ordering

Closes #592

See merge request thalia/concrexit!732

Closes #592

Improve docs for the announcements module

Closes #588

See merge request !724

Clean up and document utils package

Closes #587

See merge request !726

Fix other test warnings

See merge request !728

Suppress unclosed file handle warnings

Closes #589

See merge request !727

Fix event registration saved Dutch message

See merge request !729

One about timezones, the other about a deprecationwarning

Further improve documentation

Include docs for utils submodules

docs build needs the dev requirements as it will import commands

Further improve docs

Delete unused ci-requirements.txt

Closes #571

See merge request !725

Improve docs for the merchandise site

See merge request !723

Closes #571

Also makes the view that handles marking announcements as closed much more robust

See #570

See #570

Update available tox environments in README

See merge request thalia/concrexit!722

Add more tests to the events app

See merge request thalia/concrexit!717

Refactored documents app

Closes #268 and #519

See merge request thalia/concrexit!689

Install binary version of psycopg2

See merge request thalia/concrexit!720

Get manage.py from Django 2.0

See merge request thalia/concrexit!719

Use app configs

See merge request thalia/concrexit!721

This is recommended by the Django documentation

Move Payment model to dedicated 'payments' app

See merge request thalia/concrexit!704

Surpresses a warning and we haven't had issues with the binary package

See also http://initd.org/psycopg/docs/install.html#binary-install-from-pypi

This strips comments about Python 2 and uses Python 3 raise from exception code.

Fix coverage badge in README

See merge request thalia/concrexit!718