update Piwik to version 2.16 (fixes #91)

www/analytics/libs/bower_components/visibilityjs/lib/visibility.fallback.js

@@ -0,0 +1,55 @@
+// Add Page Visibility API support to old browsers by focus/blur hack.
+//
+// Include this script _before_ Visibility.js.
+//
+// Note, that this hack doesn’t correctly emulate Page Visibility API:
+// when user change focus from browser to another window (browser and your
+// page may stay visible), this hack will decide, that you page is hidden.
+//
+// For Firefox 5–9 it will be better to use MozVisibility hack without
+// this issue. See <https://github.com/private-face/mozvisibility>.
+;(function (document) {
+    "use strict";
+
+    if ( document.visibilityState || document.webkitVisibilityState ) {
+         return;
+    }
+
+    document.hidden = false;
+    document.visibilityState = 'visible';
+
+    var event = null
+    var i = 0
+    var fireEvent = function () {
+        if( document.createEvent ) {
+            if ( !event ) {
+                event = document.createEvent('HTMLEvents');
+                event.initEvent('visibilitychange', true, true);
+            }
+            document.dispatchEvent(event);
+        } else {
+            if ( typeof(Visibility) == 'object' ) {
+                Visibility._change.call(Visibility, { });
+            }
+        }
+    }
+
+    var onFocus = function () {
+        document.hidden = false;
+        document.visibilityState = 'visible';
+        fireEvent();
+    };
+    var onBlur  = function () {
+        document.hidden = true;
+        document.visibilityState = 'hidden';
+        fireEvent();
+    }
+
+    if ( document.addEventListener ) {
+        window.addEventListener('focus', onFocus, true);
+        window.addEventListener('blur',  onBlur,  true);
+    } else {
+        document.attachEvent('onfocusin',  onFocus);
+        document.attachEvent('onfocusout', onBlur);
+    }
+})(document);