* Bump version of pymysensors to 0.6, which includes the tcp gateway.
* Update requirements_all.txt.
* Replace CONF_PORT with CONF_DEVICE and ATTR_PORT with ATTR_DEVICE.
* Add tcp_port in config.
* Try to guess if tcp or serial gateway is configured, by validating
device name as an ip address. If successful setup tcp gateway, if it
fails, setup serial gateway.
* Update device_state_attributes to show correct device, ethernet or
serial.