update Piwik to version 2.16 (fixes #91)

www/analytics/plugins/VisitTime/Archiver.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * Piwik - Open source web analytics
+ * Piwik - free/libre analytics platform
  *
  * @link http://piwik.org
  * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
@@ -30,7 +30,15 @@ class Archiver extends \Piwik\Plugin\Archiver
             self::LOCAL_TIME_RECORD_NAME,
             self::SERVER_TIME_RECORD_NAME,
         );
-        $this->getProcessor()->aggregateDataTableRecords($dataTableRecords);
+        $columnsAggregationOperation = null;
+        $this->getProcessor()->aggregateDataTableRecords(
+            $dataTableRecords,
+            $maximumRowsInDataTableLevelZero = null,
+            $maximumRowsInSubDataTable = null,
+            $columnToSortByBeforeTruncation = null,
+            $columnsAggregationOperation,
+            $columnsToRenameAfterAggregation = null,
+            $countRowsRecursive = array());
     }
 
     protected function aggregateByServerTime()