Fixed #101 : Implement PLURIAL

Fixed #103 : Implement PlurialNodeParser
Fixed #104 : Implement dynamic concept
Fixed #107 : PrepareEvalxxxEvaluator: context hints are lost on a second evaluation

tests/core/test_SheerkaHasAManager.py

@@ -9,7 +9,10 @@ class TestSheerkaHasAManager(TestUsingMemoryBasedSheerka):
 
         king_instance = sheerka.new("king")
         res = sheerka.set_hasa(context, king_instance, kingdom)
+
         assert res.status
+        assert king_instance.get_prop(BuiltinConcepts.HASA) == {kingdom}
+        assert sheerka.hasa(king_instance, kingdom)
 
         # when global truth is not activated, only the current instance is modified
         another_king = sheerka.get_by_key("king")
@@ -56,3 +59,17 @@ class TestSheerkaHasAManager(TestUsingMemoryBasedSheerka):
         assert res.body.property_name == BuiltinConcepts.HASA
         assert res.body.property_value == kingdom
         assert res.body.concept == sheerka.new("king")
+
+    def test_i_can_set_hase_twice_when_global_truth_is_true_the_second_time(self):
+        sheerka, context, king, kingdom = self.init_concepts("king", "kingdom")
+        global_truth_context = self.get_context(sheerka, global_truth=True)
+
+        king_instance = sheerka.new("king")
+        sheerka.set_hasa(context, king_instance, kingdom)
+
+        # set it again with global_truth = True
+        res = sheerka.set_hasa(global_truth_context, king_instance, kingdom)
+
+        assert res.status
+        assert sheerka.hasa(king_instance, kingdom)
+        assert sheerka.hasa(sheerka.new("king"), kingdom)  # try another instance