Glances API RESTful implementation.

        Return the JSON representation of the couple plugin/history of item
        HTTP/200 if OK
        HTTP/400 if plugin is not found
        HTTP/404 if others error

def _api_item_history(self, plugin, item, nb=0):
        """Glances API RESTful implementation.

        Return the JSON representation of the couple plugin/history of item
        HTTP/200 if OK
        HTTP/400 if plugin is not found
        HTTP/404 if others error

        """
        return self._api_itemvalue(plugin, item, history=True, nb=int(nb))