public async Task<GeoCoords> GetLocationAsync()
        {
            var locator = new Geolocator(this._appContext) { DesiredAccuracy = 30 };
            var position = await locator.GetPositionAsync(30000);

            var result = new GeoCoords
            {
                Latitude = position.Latitude,
                Longitude = position.Longitude
            };

            return result;
        }
        public async Task<GeoCoords> GetLocationAsync()
        {
            var geolocator = new Windows.Devices.Geolocation.Geolocator();
            var geoposition = await geolocator.GetGeopositionAsync();

            var coords = new GeoCoords
            {
                Latitude = geoposition.Coordinate.Latitude,
                Longitude = geoposition.Coordinate.Longitude
            };

            return coords;
        }
        public async Task<VenuesResponse> GetVenues(string query, GeoCoords coords)
        {
            var v = DateTime.Now.ToString("yyyyMMdd");

            var ll = string.Format("{0},{1}", coords.Latitude, coords.Longitude);

            var url = string.Format(@"https://api.foursquare.com/v2/venues/search?ll={0}&query={1}&client_id={2}&client_secret={3}&v={4}", ll, query, _CLIENT_ID, _CLIENT_SECRET, v);

            var client = new HttpClient();
            var response = await client.GetStringAsync(url);

            JObject o = JObject.Parse(response);

            return await Task.Factory.StartNew(() => JsonConvert.DeserializeObject<VenuesResponse>(o["response"].ToString()));
        }