Compatibility to SF4 in FMElfinderExtension.php (#318)

I simply replace :
FMElfinderBundle:Elfinder/helper:
with :
@FMElfinder/Elfinder/helper/

Twig/Extension/FMElfinderExtension.php

@@ -52,7 +52,7 @@ public function tinymce($instance = 'default', $parameters = array('width' => 90
             throw new \Twig_Error_Runtime('The function can be applied to strings only.');
         }
 
-        return $this->twig->render('FMElfinderBundle:Elfinder/helper:_tinymce.html.twig',
+        return $this->twig->render('@FMElfinder/Elfinder/helper/_tinymce.html.twig',
             array(
                 'instance' => $instance,
                 'width'    => $parameters['width'],
@@ -77,7 +77,7 @@ public function tinymce4($instance = 'default', $parameters = array('width' => 9
             throw new \Twig_Error_Runtime('The function can be applied to strings only.');
         }
 
-        return $this->twig->render('FMElfinderBundle:Elfinder/helper:_tinymce4.html.twig',
+        return $this->twig->render('@FMElfinder/Elfinder/helper/_tinymce4.html.twig',
             array(
                 'instance' => $instance,
                 'width'    => $parameters['width'],
@@ -103,7 +103,7 @@ public function summernote($instance = 'default', $selector = '.summenote', $par
             throw new \Twig_Error_Runtime('The function can be applied to strings only.');
         }
 
-        return $this->twig->render('FMElfinderBundle:Elfinder/helper:_summernote.html.twig',
+        return $this->twig->render('@FMElfinder/Elfinder/helper/_summernote.html.twig',
             array(
                 'instance' => $instance,
                 'selector' => $selector,