If DEBUG - send exception as HTTP 500

app/FrontController.php

@@ -121,6 +121,9 @@ class FrontController
             return (!DEBUG) ? $html : Profiler::getInstance()->end($html);
         } catch(Exception $e) {
             if (DEBUG == true) {
+                if (!headers_sent()) {
+                    header('HTTP/1.0 500 Internal Server Error');
+                }
                 return ErrorHandler::showDebug($e);
             }
             $layout = new ErrorLayout();