Tests: add test project

* manage.py file at the root of the project
* targetting the project located at tests/test_project/settings.py

That allows testing the linter through just calling it on the project itself.
Using the new method coming soon: `python manage.py lintmigrations`

tests/test_project/app_drop_column/views.py

@@ -0,0 +1,6 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.shortcuts import render
+
+# Create your views here.