* [DJ1.11] Use a dict instead of django.template.Context

* [Travis] update travis badge to match current branch

* [Travis] Emit all warnings during tests

* [DJ1.9] Remove warning of not declaring explicit app_label

Example:

RemovedInDjango19Warning: Model class helios.models.Voter doesn't declare an explicit app_label and either isn't in an application in INSTALLED_APPS or else was imported before its application was loaded. This will no longer be supported in Django 1.9.

(cherry picked from commit 693acef9e4c3b093d5bf2bc1655e6f53a6dd4007)

* [DJ1.10] list of urlpatterns is a list of url() instead of a patterns() result

* [DJ1.10] Support for string view arguments to url() will be removed

* [DJ1.9] Add used django.contrib apps in installed apps

* Remove traces of south (now unused)

* Upgrade celery

* [DJ1.9] Fix some imports for django 1.9

* A bit more homogeneous redirect creation

* Improvements to tests

* [DJ1.9] Pre-fix tests for Django 1.9

* Fixed election sorting in admin elections page

* [DJ1.10] Redefine template settings

* [Travis] Upgrade pip instead of fixing setuptools' version

* [DJ1.9] Cannot import models from a django-app init (even as third-party import)

* Use urlparse.parse_qs instead of cgi.parse_qs (deprecated)

* Explicit some more imports removing almost all conflicting 'import *'

* Restore functionality of extract-passwords-for-email

* Upgrade Django to 1.9

* [DJ1.10] SubfieldBase has been deprecated. Use Field.from_db_value instead.

* Silence urls.W002 warning.

Slashes aren't deemed necessary at start of URL patterns, but the actual check author recognized the too-strict approach for his check: https://stackoverflow.com/a/41450355



* [DJ2] on_delete will be a required arg for ForeignKey, currently defaults to models.CASCADE.

* [DJ1.10] Upgrade Celery to 4.2.1, Kombu to 4.2.0

Should probably integrate with django-celery-results and/or django-celery-beat

* [DJ2] SelectDateWidget is moved out of extras

* [tests] Extend setup_login capabilities

* [tests] Add admin user fixture and test accessibility of stats

* [DJ1.10] Update stats_urls to have names and be reversed by name

* [DJ1.10] Update election_urls to have names and be reversed by name

* [DJ1.10] reverse function is now in django.urls

* [DJ1.10] Update helios.urls to have names and be reversed by name

* Make stats_url_names and election_url_names visible from url_names

* [DJ1.10] Update helios_auth.urls to have names and be reversed by name

* [DJ1.10] Upgrade to Django 1.10

* [DJ1.11] Fix widgets

* [DJ1.11] Upgrade to Django 1.11

* [Travis] Test to run travis on both Xenial and Trusty

* [Travis] Postgres 9.3 isn't present in Xenial

* Fix csrf_token on perms_why

* [DJ2] Update HSTS Middleware to latest definition

* Bump Django to 1.11.28

* [DJ1.8+] remove unneeded django-sslify and django-secure

* [celery] Make celery backend configurable

Also only use eager using testing, even if it is not recommended

* [readme] revert travis badge to benadida/helios-server

* add recent significant contributors

Co-authored-by: Marco Ciotola <848222@stud.unive.it>
Co-authored-by: Douglas Cerna (Soy Douglas) <douglascerna@yahoo.com>
Co-authored-by: Ben Adida <ben@adida.net>