Feature/#274 (#281)

* #274 added acceptance tests, need to work out failing unit tests but probably going to be a redesign where we hold a reference to the cookie container and empty it if needed

* #274 updated code coverage value

* #274 offloaded cache logic to builder in preparation for adding state

* #274 hacked something together but this is not right approach

* #274 updated defaults and docs

* #274 updated code coverage

test/Ocelot.UnitTests/Requester/HttpClientHttpRequesterTest.cs

@@ -35,7 +35,10 @@ namespace Ocelot.UnitTests.Requester
                 .Setup(x => x.CreateLogger<HttpClientHttpRequester>())
                 .Returns(_logger.Object);
             _cacheHandlers = new Mock<IHttpClientCache>();
-            _httpClientRequester = new HttpClientHttpRequester(_loggerFactory.Object, _cacheHandlers.Object, _house.Object);            
+            _httpClientRequester = new HttpClientHttpRequester(
+                _loggerFactory.Object, 
+                _cacheHandlers.Object, 
+                _house.Object);            
         }
 
         [Fact]