Add binding for IR-SEEK to spec

[angustrau-old]

The spec does not currently specify a way to allow the use the seeker functionality provided by the EV3 infrared sensor through the central API.

[ddemidov]

You should be able to set the InfraredSensor mode to IR-SEEK. See here for the description of modes/values for the sensor: http://www.ev3dev.org/docs/sensors/lego-ev3-infrared-sensor/. Is that not enough for your tasks?