Fix for #246 - ActionLink generating wrong urls

There's an overload that's missing from ActionLink but is present on url
helper, making it very easy to mistakenly pass the wrong data. In the case
of #246, the controller name is treated as the route-values and the
route-values treated as html attributes, leading to the wrong link being
generated.

src/Microsoft.AspNet.Mvc.Core/Rendering/HtmlHelperLinkExtensions.cs

@@ -71,6 +71,24 @@ namespace Microsoft.AspNet.Mvc.Rendering
                 htmlAttributes: null);
         }
 
+        public static HtmlString ActionLink<TModel>(
+            [NotNull] this IHtmlHelper<TModel> helper,
+            [NotNull] string linkText,
+            string actionName,
+            string controllerName,
+            object routeValues)
+        {
+            return helper.ActionLink(
+                linkText,
+                actionName,
+                controllerName,
+                protocol: null,
+                hostname: null,
+                fragment: null,
+                routeValues: routeValues,
+                htmlAttributes: null);
+        }
+
         public static HtmlString ActionLink<TModel>(
             [NotNull] this IHtmlHelper<TModel> helper, 
             [NotNull] string linkText,