Get tests to run under Django 1.4 and 1.5, but without duplication on 1.6 and later

wiki/tests/__init__.py

-from .test_basic import *
+from __future__ import absolute_import
+
+import django
+if django.VERSION < (1, 6):
+    # New style autodiscovery of tests doesn't work for Django < 1.6,
+    # and we don't want to duplicate tests for Django >= 1.6
+    from .test_basic import *