Fixed #68: Implement SheerkaQL

Fixed #70: SheerkaFilterManager : Pipe functions
Fixed #71: SheerkaFilterManager : filter_objects
Fixed #75: SheerkaMemory: Enhance memory() to use the filtering capabilities
Fixed #76: SheerkaEvaluateConcept: Concepts that modify the state of the system must not be evaluated during question

tests/parsers/test_DefConceptParser.py

@@ -671,7 +671,7 @@ from give me the date !
 
         assert not res.status
         assert sheerka.isinstance(res.value, BuiltinConcepts.ERROR)
-        assert sheerka.has_error(res, __type="SyntaxErrorNode", message="Empty 'auto_eval' declaration.")
+        assert sheerka.has_error(context, res, __type="SyntaxErrorNode", message="Empty 'auto_eval' declaration.")
 
     def test_i_cannot_parse_when_wrong_auto_eval_value(self):
         sheerka, context, parser, *concepts = self.init_parser()
@@ -709,4 +709,4 @@ from give me the date !
 
         assert not res.status
         assert sheerka.isinstance(res.value, BuiltinConcepts.ERROR)
-        assert sheerka.has_error(res, __type="SyntaxErrorNode", message="Empty 'def_var' declaration.")
+        assert sheerka.has_error(context, res, __type="SyntaxErrorNode", message="Empty 'def_var' declaration.")