Upgraded Protobuf, and added api support for it

MediaBrowser.Model/Entities/ItemSpecialCounts.cs

@@ -1,14 +1,23 @@
-
+using ProtoBuf;
+
 namespace MediaBrowser.Model.Entities
 {
     /// <summary>
     /// Since it can be slow to collect this data, this class helps provide a way to calculate them all at once.
     /// </summary>
+    [ProtoContract]
     public class ItemSpecialCounts
     {
+        [ProtoMember(1)]
         public int RecentlyAddedItemCount { get; set; }
+
+        [ProtoMember(2)]
         public int RecentlyAddedUnPlayedItemCount { get; set; }
+
+        [ProtoMember(3)]
         public int InProgressItemCount { get; set; }
+
+        [ProtoMember(4)]
         public decimal PlayedPercentage { get; set; }
     }
 }