anchor: Body:setSleepingAllowed
  Sets the sleeping behaviour of the body. Should sleeping be allowed, a body at rest will automatically sleep. A sleeping body is not simulated unless it collided with an awake body. Be wary that one can end up with a situation like a floating sleeping body if the floor was removed.
  Body:setSleepingAllowed( allowed )
  allowed boolean True if the body is allowed to sleep or false if not.