Build improvements (#569)

* Black linting

* Adding Black to dev dependencies and upping minimal python to 3.6.2 for compatibility

* Updating packages

* Removing pip-tools input and exporting requirements with poetry

* Deleting old setup files and test runner

* Trying 1.3.7

* Looser extras requirements to prevent conflicts

* Sorted imports with isort

* Added iSort to dev dependencies

* Fixes localtime for naive setups

django_q/migrations/0001_initial.py

@@ -1,6 +1,6 @@
-from django.db import models, migrations
-import picklefield.fields
 import django.utils.timezone
+import picklefield.fields
+from django.db import migrations, models
 
 
 class Migration(migrations.Migration):