Updates the RequiresExecution logic so we can skip steps based on some user input (i.e. skip the starter kit installation). Fixes the start kit js stuff to update the model correctly and continue. Fixes the error view to restart - it cannot just go back because there might not be a view there.

src/Umbraco.Web/Install/InstallSteps/StarterKitInstallStep.cs

@@ -45,7 +45,7 @@ namespace Umbraco.Web.Install.InstallSteps
             installer.InstallBusinessLogic(manifestId, packageFile);            
         }
 
-        public override bool RequiresExecution()
+        public override bool RequiresExecution(object model)
         {            
             var installSteps = InstallStatusTracker.GetStatus().ToArray();
             //this step relies on the preious one completed - because it has stored some information we need