Merge pull request #67 from johnallers/webproxy-bug

Fixed issue that causes the Quidjibo to stop when it fails to retrieve work items.

src/Quidjibo/Servers/QuidjiboServer.cs

@@ -151,7 +151,7 @@ private async Task WorkLoopAsync(string queue)
                     _throttle.Release();
                 }
 
-                if (items.Count <= 0)
+                if (items == null || items.Count <= 0)
                 {
                     await Task.Delay(pollingInterval, _cts.Token);
                 }