* modbus: support multiple modbus hub
* update data after entities added
* pass hub object to each entity. and save hub to hass.data but not in module level
* add hub_client setup log
* don't update when adding device, because hub_client is not ready right now
* support restore last state
* remove useless func
* compatible with python35
* removed unrelated style changes
* Update flexit for multi-device modbus
* change how hubs are referenced in the configuration
* Also update climate/modbus.py
* Remove unwanted whitescapce
* Defined common constants centrally
* Update DOMAIN in climate and switch components
* Removed unnecessary vol.schema
* Make hub name optional
* Add name property to ModbusHub