Content base template now outputs attributes and classes

--HG--
branch : 1.x

src/Orchard.Web/Core/Contents/Views/Content.cshtml

@@ -4,9 +4,14 @@
         Layout.Title = Model.Title;
     }
 
+    Model.Classes.Add("content-item");
+    
     var contentTypeClassName = ((string)Model.ContentItem.ContentType).HtmlClassify();
+    Model.Classes.Add(contentTypeClassName);
+    
+    var tag = Tag(Model, "article");
 }
-<article class="content-item @contentTypeClassName">
+@tag.StartElement
     <header>
         @Display(Model.Header)
         @if (Model.Meta != null) {
@@ -21,4 +26,4 @@
             @Display(Model.Footer)
         </footer>
     }
-</article>
+@tag.EndElement