Improve web finalisation navigation, caching and Anot support

tests/test_add_final_score.py

@@ -103,6 +103,8 @@ class AddFinalScoreTests(unittest.TestCase):
             self.assertFalse((student / "answers" / "001 - Ex 1.jpg").exists())
             self.assertEqual((output / "histogramme.pdf").read_bytes(), b"histogram")
             self.assertEqual(read_json(output / "stat.json"), {"Ex 1": "4.0"})
+            self.assertEqual(read_json(root / '.copienator/final_scores.json'),
+                             {'version': 1, 'copies': {'1': {'name': 'Student', 'score': '12.3'}}})
 
     def test_omits_answers_directory_when_it_was_not_generated(self):
         with tempfile.TemporaryDirectory() as temporary: