PEP8-ify PR #67 and fix trailing whitespace

Camp rule: leave things in a better state then you found it.

polymorphic/tests.py

@@ -845,7 +845,7 @@ class PolymorphicTests(TestCase):
         self.assertEqual(p, t.superclass)
         self.assertEqual(p.related_name_subclass, t)
 
-        #test that we can delete t 
+        #test that we can delete the object
         t.delete()