Added missing currently_playing_type field to PlaybackContext (#292)

SpotifyAPI.Web/Enums/TrackType.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace SpotifyAPI.Web.Enums
+{
+    [Flags]
+    public enum TrackType
+    {
+        [String("track")]
+        Track = 1,
+
+        [String("episode")]
+        Episode = 2,
+
+        [String("ad")]
+        Ad = 4,
+
+        [String("unknown")]
+        Unknown = 8
+    }
+}

SpotifyAPI.Web/Models/PlaybackContext.cs

@@ -31,5 +31,9 @@ namespace SpotifyAPI.Web.Models
 
         [JsonProperty("item")]
         public FullTrack Item { get; set; }
+
+        [JsonProperty("currently_playing_type")]
+        [JsonConverter(typeof(StringEnumConverter))]
+        public TrackType CurrentlyPlayingType { get; set; }
     }
 }