Feature/expose http handlers (#224)

* temp commit

* trying to work out how to expose the http handlers in a decent way..

* pissing about at lunch

* changed to func so you can instanciate object or new it up each time

* docs for dele handlers

* upgraded to sdk 2.1.4

* some validation for consul services

test/Ocelot.UnitTests/Requester/FakeDelegatingHandler.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Ocelot.UnitTests.Requester
+{
+    public class FakeDelegatingHandler : DelegatingHandler
+    {
+        public FakeDelegatingHandler()
+        {
+
+        }
+
+        public FakeDelegatingHandler(int order)
+        {
+            Order = order;
+        }
+        public int Order {get;private set;}
+        public DateTime TimeCalled {get;private set;}
+
+        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            TimeCalled = DateTime.Now;
+            return new HttpResponseMessage();
+        }
+    }
+}