Remove groundControl implementation to be done by the attendee

Conflicts:

	messages/src/main/scala/fr/xebia/xke/akka/airport/InitGroundControl.scala
	server/app/fr/xebia/xke/akka/game/SingleAirportGame.scala
	server/test/fr/xebia/xke/akka/game/GroundControlSpec.scala
Remove the first order in AirTrafficControl