Unify database configuration

This commit standardizes on PostGIS for all environments and moves the
database configuration into base.py, making use of the fact that we can
use environment variables to change connection information rather than
maintaining separate configuration files.
Remove TEST_RUNNER setting

Running ``manage.py test`` was throwing "ImportError: No module named
discover_runner."

The Django 1.7 docs say: "By default, TEST_RUNNER points to
'django.test.runner.DiscoverRunner'"
Merge pull request #47 from jwalgran/topic/remove-test-runner-setting

Remove TEST_RUNNER setting
Set up CRLF handling for Windows clients
Create Django apps with models, URLs, and view stubs

* Keep `core` app small (with no UI, and just the ubiquitous User and Group models)
* Create topic-specific apps for handling groups of models and the URLs that service them
* Name all URLs (usually the view name)
* Use a `urls` module where an app handles URLs with more than one prefix
* Create view stubs for all URLs and import where referenced
* Create stubs for decorators and import where referenced
* Add apps to `settings.LOCAL_APPS`
* Distribute all models from `doc/draft-models.py` and all URLs from `doc/draft-urls.py`

Note that it all loads in our `app` VM using this command:
     envdir /etc/nyc-trees.d/env ./manage.py shell
Include Pillow in Django requirements
Silence warning about test runner

It generates false positives and is being removed (https://code.djangoproject.com/ticket/23469)
Merge pull request #43 from RickMohr/make-apps-and-urls

Create Django apps with models, URLs, and view stubs
Merge pull request #44 from jwalgran/topic/unify-db-config

Unify database configuration
Add missing import to settings/base.py

In 791faa94 I moved the database config to base.py but did not import
the required ``environ`` function.
Merge pull request #50 from jwalgran/fix/add-missing-settings-import

Add missing import to settings/base.py