Added comment.py and metaclasses.py

metaclasses.py

@@ -0,0 +1,8 @@
+import itertools
+
+class InstanceCounterMeta(type):
+    """ Metaclass to make instance counter not share count with descendants
+    """
+    def __init__(cls, name, bases, attrs):
+        super().__init__(name, bases, attrs)
+        cls._ids = itertools.count(1)