[SearchEngine] Add code documentation

lib/Alchemy/Phrasea/SearchEngine/AbstractConfigurationPanel.php

@@ -1,14 +1,31 @@
 <?php
 
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2012 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Alchemy\Phrasea\SearchEngine;
 
 abstract class AbstractConfigurationPanel implements ConfigurationPanelInterface
 {
+    /**
+     * Return the path to the file where the configuration is saved
+     * 
+     * @return string The path to the file
+     */
     public function getConfigPathFile()
     {
         return __DIR__ . '/../../../../config/'.$this->getName().'.json';
     }
 
+    /**
+     * {@inheritdoc}
+     */
     public function getAvailableDateFields(array $databoxes)
     {
         $date_fields = array();