Feature/#246 (#252)

* failing test

* failing test but needs real butterfly server running..need to fix that...also worked out ive broken tracing...yey

* brought in butterfly source code so i can work out how to write acceptance tests for this...

* fixed the bug but still need to fix tracing

* tracing working again across services but need to make tracing hook into new Ocelot middleware as it still uses asp.net middleware

* removed butterfly libs brought in for testing

test/Ocelot.UnitTests/Requester/TracingHandlerFactoryTests.cs

@@ -0,0 +1,27 @@
+using Butterfly.Client.Tracing;
+using Moq;
+using Ocelot.Requester;
+using Shouldly;
+using Xunit;
+
+namespace Ocelot.UnitTests.Requester
+{
+    public class TracingHandlerFactoryTests
+    {
+        private TracingHandlerFactory _factory;
+        private Mock<IServiceTracer> _tracer;
+
+        public TracingHandlerFactoryTests()
+        {
+            _tracer = new Mock<IServiceTracer>();
+            _factory = new TracingHandlerFactory(_tracer.Object);
+        }
+
+        [Fact]
+        public void should_return()
+        {
+            var handler = _factory.Get();
+            handler.ShouldBeOfType<OcelotHttpTracingHandler>();
+        }
+    }
+}