Fixed #32 : concept groups are not correctly updated

Fixed #35 : Refactor test helper class (CNC, CC, CIO)
Fixed #36 : Concept values are not used when declared with variable expression
Fixed #37 : Objects in memory lose their values are restart
Fixed #38 : func(a=b, c) (which is not allowed) raise an exception

tests/core/test_SheerkaConceptManager.py

@@ -487,6 +487,9 @@ class TestSheerkaConceptManager(TestUsingMemoryBasedSheerka):
         assert get_concept_attrs(foo) == ["b", "c"]
         assert get_concept_attrs(new_concept) == ["b", "c"]
 
+        new_foo = sheerka.new(foo)
+        assert get_concept_attrs(new_foo) == ["b", "c"]
+
     def test_key_is_modified_when_modifying_name_or_variables(self):
         sheerka, context, foo = self.init_concepts(Concept("foo a b").def_var("a").def_var("b"))