imported signalr 1.1.3 into NzbDrone.

src/Microsoft.AspNet.SignalR.Core/Infrastructure/ListHelper.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.md in the project root for license information.
+
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+
+namespace Microsoft.AspNet.SignalR.Infrastructure
+{
+    internal class ListHelper<T>
+    {
+        public static readonly IList<T> Empty = new ReadOnlyCollection<T>(new List<T>());
+    }
+}