Fixed #43 : BnfNodeParser: I can recognize when multiple level of ISA

Fixed #44 : BnfNodeParser: I must simplify results when multiple levels of ISA
Fixed #45 : Dynamic variables cannot be parsed at restart
Fixed #46 : Concepts variables values are transformed into list by default
Fixed #47 : SheerkaAdmin. Add min, max, mean time when restoring files

tests/TestUsingFileBasedSheerka.py

@@ -26,7 +26,7 @@ class TestUsingFileBasedSheerka(BaseTest):
             TestUsingFileBasedSheerka.ontologies_created.clear()
 
     @staticmethod
-    def new_sheerka_instance(cache_only):
+    def new_sheerka_instance(cache_only=False):
         sheerka = Sheerka(cache_only=cache_only)
         sheerka.initialize(SHEERKA_TEST_FOLDER,
                            save_execution_context=False,