imported signalr 1.1.3 into NzbDrone.

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

@@ -0,0 +1,16 @@
+using System.Threading;
+
+namespace Microsoft.AspNet.SignalR.Infrastructure
+{
+
+    public static class InterlockedHelper
+    {
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1045:DoNotPassTypesByReference", MessageId = "0#", Justification="This is an interlocked helper...")]
+        public static bool CompareExchangeOr(ref int location, int value, int comparandA, int comparandB)
+        {
+            return Interlocked.CompareExchange(ref location, value, comparandA) == comparandA ||
+                   Interlocked.CompareExchange(ref location, value, comparandB) == comparandB;
+        }
+    }
+
+}