Do not use `hasattr` in `Group.__getattr__` to check for `_group_attribute_access_active` -- this easily leads to infinite recursions in Python3. Instead, check using `in self.__dict__`.
Allow any kind of number (not only integers) for the record argument in `StateMonitor` (will be converted to `int32`). In Python3, a simple expression such as `N/2` is a float, not an int.