--fix Twig2 compatibility

Author: adambalint-srg

src/Mandango/Mondator/ClassExtension.php

@@ -340,8 +340,9 @@ protected function processTemplate(Definition $definition, $name, array $variabl
         $variables['class'] = $this->class;
         $variables['config_class'] = $this->configClass;
         $variables['config_classes'] = $this->configClasses;
-
-        $result = $twig->loadTemplate($name)->render($variables);
+	
+		$template = $twig->createTemplate($name);
+		$result = $template->render($variables);
 
         // properties
         $expression = '/
@@ -409,7 +410,7 @@ public function getTwig()
                 throw new \RuntimeException('Twig is required to use templates.');
             }
 
-	          $loader = new \Twig_Loader_String();
+			$loader = new \Twig_Loader_Array();
             $twig = new \Twig_Environment($loader, array(
                 'autoescape'       => false,
                 'strict_variables' => true,