added cliff sensor
added cliff sensor

EricssonResearch/scott-eu,EricssonResearch/scott-eu,EricssonResearch/scott-eu,EricssonResearch/scott-eu,EricssonResearch/scott-eu,EricssonResearch/scott-eu,EricssonResearch/scott-eu,EricssonResearch/scott-eu,EricssonResearch/scott-eu,EricssonResearch/scott-eu