added count api methods for studios and genres

MediaBrowser.Model/Dto/ItemByNameCounts.cs

@@ -31,5 +31,20 @@ namespace MediaBrowser.Model.Dto
         /// </summary>
         /// <value>The game count.</value>
         public int GameCount { get; set; }
+        /// <summary>
+        /// Gets or sets the trailer count.
+        /// </summary>
+        /// <value>The trailer count.</value>
+        public int TrailerCount { get; set; }
+        /// <summary>
+        /// Gets or sets the song count.
+        /// </summary>
+        /// <value>The song count.</value>
+        public int SongCount { get; set; }
+        /// <summary>
+        /// Gets or sets the album count.
+        /// </summary>
+        /// <value>The album count.</value>
+        public int AlbumCount { get; set; }
     }
 }