Implemented some enhancement request and fixed some bugs

Fixed #2 : Variables are not recognized when inside a rule token
Fixed #15 : Rule: rete attributes are lost when a new ontology is created
Fixed #14 : ReteNetwork: Format rules must not be added to Rete network
Fixed #16 : DefConcept: Variables are not recognized when they are keyword arguments
Fixed #4 : Comparison are not correctly set when comparison property is a concept
Fixed #14 : Parser: merge FunctionParser.NamesNode and ExpressionParser.NamesNode
Fixed #18 : Parser: Add SourceCodeNode test to UnrecognizedNodeParser
Fixed #20 : At startup Number concept is saved in db a numerous number of time
Fixed #21 : CacheManager: I can remove all elements from a ListIfNeededCache and fill it again
Fixed #22 : CacheManager: I can remove all elements from a SetCache and fill it again
Fixed #23 : HistoryManager: history() no longer works
Fixed #24 : HistoryManager: history() no longer works after creating an exec rule
Fixed #25 : SheerkaMemory: Use MemoryObject instead of sheerka.local
Fixed #26 : Debugger: add the list all available services..
Fixed #27 : CONCEPTS_GRAMMARS_ENTRY does not seems to be in use any more
Fixed #28 : Give order to services

tests/core/test_ast_helper.py

@@ -1,8 +1,8 @@
 import ast
 
 import pytest
-from core.ast_helpers import UnreferencedNamesVisitor, UnreferencedVariablesVisitor
 
+from core.ast_helpers import UnreferencedNamesVisitor, UnreferencedVariablesVisitor
 from tests.TestUsingMemoryBasedSheerka import TestUsingMemoryBasedSheerka
 
 
@@ -13,7 +13,8 @@ class TestAstHelper(TestUsingMemoryBasedSheerka):
         ("date.today()", {"date"}),
         ("test()", {"test"}),
         ("sheerka.test()", {"sheerka"}),
-        ("for i in range(10): pass", set())
+        ("for i in range(10): pass", set()),
+        ("func(x=a, y=b)", {"func", "a", "b"}),
 
     ])
     def test_i_can_get_unreferenced_names_from_simple_expressions(self, source, expected):
@@ -31,8 +32,8 @@ class TestAstHelper(TestUsingMemoryBasedSheerka):
         ("date.today()", set()),
         ("test()", set()),
         ("sheerka.test()", set()),
-        ("for i in range(10): pass", set())
-
+        ("for i in range(10): pass", set()),
+        ("func(x=a, y=b)", {"a", "b", "x", "y"}),
     ])
     def test_i_can_get_unreferenced_variables_from_simple_expressions(self, source, expected):
         context = self.get_context()