add the hotel_id to the avaliablity request params,add api_key request param to examples,add city id to the hotels response, move nights avaliablity response param to object level instead of room object level, move room_id avaliablity response param to room object level instead of room.image object level.
Split avaliability response to two responses according to request params, response for city_id,hotel_ids and another one for hotel_id
fix documentation