Configure settings for docs using test function (not sandbox)

This avoids a pesky autodoc import issue that the debug toolbar creates when it
patches the URL conf.  It was preventing the EventHandler class from
being loaded via autodoc.  This fix solves that issue.

docs/source/conf.py

@@ -21,13 +21,11 @@ import sys
 import os
 oscar_folder = os.path.realpath(
     os.path.join(os.path.dirname(__file__), '../..'))
-sandbox_folder = os.path.realpath(
-    os.path.join(os.path.dirname(__file__), '../../sites/sandbox'))
 sys.path.append(oscar_folder)
-sys.path.append(sandbox_folder)
 
-# Specify settings module
-os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings')
+# Specify settings module (which will be picked up from the sandbox)
+from tests.config import configure
+configure()
 
 # -- General configuration -----------------------------------------------------