jQuery3: adding migration tool for debugging

this will output error logs in the browser console
for lines that need to be changed to use jQuery 3

abandon this patch after testing is done

Change-Id: I51ffd676e1db4a9b11d8fff0a0845da0f43882e7

htdocs/lib/web.php

@@ -218,6 +218,7 @@ function smarty($javascript = array(), $headers = array(), $pagestrings = array(
     // Make jQuery accessible with $j (Mochikit has $)
     $javascript_array[] = $jsroot . 'jquery/jquery.js';
     $headers[] = '<script type="application/javascript">$j=jQuery;</script>';
+    $headers[] = '<script src="https://code.jquery.com/jquery-migrate-3.0.1.js"></script>';
 
     // If necessary, load MathJax configuration
     if (get_config('mathjax')) {