Allow AJAX handlers to pipe objects to Laravel

Treat non scalar, non array, non RedirectResponse, non null as a Laravel compatible response
This brings AJAX handlers in line with page cycles, which do the same thing if the response is not a string. However in AJAX we should treat any scalar as a "result", not just a string. For all else (where not null), let Laravel handle it as a custom response object -- could be a model for serialization, or anything compatible.
Importantly to note when a custom redirect is sent, October's workflow is completely wiped out, so any partial updates, redirects, etc. will not occur. This is a normal and fair expectation.
Fixes #1784

modules/backend/classes/Controller.php

@@ -426,11 +426,12 @@ class Controller extends Extendable
                 }
 
                 /*
-                 * If the handler returned a redirect, process it so framework.js knows to redirect
+                 * If the handler returned a redirect, process the URL and dispose of it so
-                 * the browser and not the request!
+                 * framework.js knows to redirect the browser and not the request!
                  */
                 if ($result instanceof RedirectResponse) {
                     $responseContents['X_OCTOBER_REDIRECT'] = $result->getTargetUrl();
+                    $result = null;
                 }
                 /*
                  * No redirect is used, look for any flash messages
@@ -448,14 +449,18 @@ class Controller extends Extendable
 
                 /*
                  * If the handler returned an array, we should add it to output for rendering.
-                 * If it is a string, add it to the array with the key "result".
+                 * If it is a scalar, add it to the array with the key "result".
+                 * Otherwise, pass it to Laravel as a response object.
                  */
                 if (is_array($result)) {
                     $responseContents = array_merge($responseContents, $result);
                 }
-                elseif (is_string($result)) {
+                elseif (is_scalar($result)) {
                     $responseContents['result'] = $result;
                 }
+                elseif ($result !== null) {
+                    return $result;
+                }
 
                 return Response::make()->setContent($responseContents);
             }

modules/cms/classes/Controller.php

@@ -638,23 +638,28 @@ class Controller
                 }
 
                 /*
-                 * If the handler returned a redirect, process it so framework.js knows to redirect
+                 * If the handler returned a redirect, process the URL and dispose of it so
-                 * the browser and not the request!
+                 * framework.js knows to redirect the browser and not the request!
                  */
                 if ($result instanceof RedirectResponse) {
                     $responseContents['X_OCTOBER_REDIRECT'] = $result->getTargetUrl();
+                    $result = null;
                 }
 
                 /*
                  * If the handler returned an array, we should add it to output for rendering.
-                 * If it is a string, add it to the array with the key "result".
+                 * If it is a scalar, add it to the array with the key "result".
+                 * Otherwise, pass it to Laravel as a response object.
                  */
                 if (is_array($result)) {
                     $responseContents = array_merge($responseContents, $result);
                 }
-                elseif (is_string($result)) {
+                elseif (is_scalar($result)) {
                     $responseContents['result'] = $result;
                 }
+                elseif ($result !== null) {
+                    return $result;
+                }
 
                 return Response::make($responseContents, $this->statusCode);
             }