update Piwik to version 2.16 (fixes #91)

www/analytics/config/environment/dev.php

@@ -0,0 +1,12 @@
+<?php
+
+return array(
+
+    'Piwik\Cache\Backend' => DI\object('Piwik\Cache\Backend\ArrayCache'),
+
+    'Piwik\Translation\Loader\LoaderInterface' => DI\object('Piwik\Translation\Loader\LoaderCache')
+        ->constructor(DI\get('Piwik\Translation\Loader\DevelopmentLoader')),
+    'Piwik\Translation\Loader\DevelopmentLoader' => DI\object()
+        ->constructor(DI\get('Piwik\Translation\Loader\JsonFileLoader')),
+
+);