Refactored Caching, Refactored BnfNodeParser, Introduced Sphinx

tests/core/test_sheerka_call_parsers.py

@@ -135,6 +135,11 @@ class ListOfNoneParser(BaseTestParser):
 
 
 class TestSheerkaExecuteParsers(TestUsingMemoryBasedSheerka):
+    @classmethod
+    def teardown_class(cls):
+        # At the end of the tests, sheerka singleton instance will be corrupted
+        # Ask for a new one
+        TestUsingMemoryBasedSheerka.singleton_instance = None
 
     def test_disabled_parsers_are_not_executed(self):
         sheerka = self.get_sheerka()