[Bug 1015334] Workaround mapbox multiple-city-with-same-name issue, and cosmetic/l10n tweaks.
Update LICENSE date.
Install Django Rest Framework and dependencies.

* Markdown == 2.4
* django-filter == 0.7
* djangorestframework == 2.3.13
[Fix bug 1011044] New custom icon set.

Includes close, t-shirt, crown, and ~200 fewer unused icons.
[docs] Update Contributing Section in docs.

* Add testing details
* Add linting step
* Add CONTRIBUTING.md
Merge pull request #965 from glogiotatidis/docs-contributing

[docs] Update Contributing Section in docs.
Merge pull request #962 from Sancus/geofixes

[Bug 1015334] Workaround mapbox multiple-city-with-same-name issue, and cosmetic/l10n tweaks.
A bunch of Geolocation fixes.
Merge pull request #966 from glogiotatidis/location-fixes

A bunch of Geolocation fixes.