Updating some SpecFlow tests including fixing and extending one of the blog tests (for live writer)

Also updated SendKnownResponseHeader to pick up the Content-Type

--HG--
branch : dev

src/Orchard.Specs/Bindings/WebAppHosting.cs

@@ -233,6 +233,11 @@ namespace Orchard.Specs.Bindings {
             Assert.That(Details.StatusDescription, Is.EqualTo(statusDescription));
         }
 
+        [Then(@"the content type should be ""(.*)""")]
+        public void ThenTheContentTypeShouldBe(string contentType) {
+            Assert.That(Details.ResponseHeaders["Content-Type"], Is.StringMatching(contentType));
+        }
+
         [Then(@"I should see ""(.*)""")]
         public void ThenIShouldSee(string text) {
             Assert.That(Details.ResponseText, Is.StringMatching(text));