added SnapshotId to FullPlaylist (#227)

Author: lukaswagner

SpotifyAPI/Web/Models/FullPlaylist.cs

@@ -36,6 +36,9 @@ public class FullPlaylist : BasicModel
         [JsonProperty("public")]
         public Boolean Public { get; set; }
 
+        [JsonProperty("snapshot_id")]
+        public string SnapshotId { get; set; }
+
         [JsonProperty("tracks")]
         public Paging<PlaylistTrack> Tracks { get; set; }