Refs #6 — Fix generator.next()

`next()` does not exist anymore in Python 3.

Author: wo0dyn

demo/demo_chunkator/tests.py

@@ -113,7 +113,7 @@ def test_chunk_uuid(self):
     def test_chunk_missing_pk(self):
         with self.assertRaises(MissingPkFieldException):
             result = chunkator(User.objects.all().values("name"), 10)
-            result.next()
+            six.next(result)
 
 
 class ChunkatorWhereTest(TestCase):