improve export to add filtering parameters on result

The csv formatter now add a message about filtering parameters.

The filterInterface has been adapted to render a message.

Export/ExportManager.php

@@ -429,7 +429,7 @@ class ExportManager
         
         /* @var $formatter Formatter\CSVFormatter */
         $formatter = $this->getFormatter($this->getFormatterAlias($data));
-        $filters = array();
+        $filtersData = array();
         $aggregatorsData = array();
         
         if ($query instanceof QueryBuilder) {
@@ -440,12 +440,18 @@ class ExportManager
             }
         }
         
+        $filters = $this->retrieveUsedFilters($data[ExportType::FILTER_KEY]);
+        
+        foreach($filters as $alias => $filter) {
+            $filtersData[$alias] = $data[ExportType::FILTER_KEY][$alias]['form'];
+        }
+        
         return $formatter->getResponse(
               $result, 
               $formatterData, 
               $exportAlias, 
               $data[ExportType::EXPORT_KEY],
-              $filters, 
+              $filtersData, 
               $aggregatorsData);
     }