Trial->Paid conversion tracking with GTM

* Added trial to paid conversion tracking with GTM
* Removed WHMCS roundtrip from Showbuilder
* Moved all Analytics code into common/GoogleAnalytics.php
* Added a new Thank You page after plan changes to capture conversions
* Added a ConversionTracking plugin to facilitate that
* Also backported some minor staticBaseDir compatibility changes
* Fixed a logic error in creating the baseDir

airtime_mvc/application/controllers/plugins/ConversionTracking.php

@@ -0,0 +1,21 @@
+<?php
+
+class Zend_Controller_Plugin_ConversionTracking extends Zend_Controller_Plugin_Abstract
+{
+    public function preDispatch(Zend_Controller_Request_Abstract $request)
+    {
+        //If user is a super admin and old plan level is set to trial....
+        if (Application_Common_GoogleAnalytics::didPaidConversionOccur($request))
+        {
+            //Redirect to Thank you page, unless the request was already going there...
+            if ($request->getControllerName() != 'thank-you')
+            {
+                $request->setModuleName('default')
+                    ->setControllerName('thank-you')
+                    ->setActionName('index')
+                    ->setDispatched(true);
+            }
+        }
+    }
+
+}