Get ice servers via xirsys

Xirsys is used to get working ice servers. A call is made to a script on
the server (which has the necessary xirsys credentials), which in turn
get the data from xirsys and return to client.

js/comm.js

@@ -41,6 +41,28 @@ window.addEventListener('load', function(){
     ********************************************************************************************************************************
     */
 
+    //Get ice servers
+    let xhr = new XMLHttpRequest();
+
+    xhr.onreadystatechange = function(e){
+        if(xhr.readyState == 4 && xhr.status == 200){
+            let res = JSON.parse(xhr.responseText);
+
+            servers = res.iceServers ? res : servers;
+        }
+    }
+
+    xhr.open("GET", "/Server.php", true);
+    xhr.send();
+    
+    /*
+    ********************************************************************************************************************************
+    ********************************************************************************************************************************
+    ********************************************************************************************************************************
+    ********************************************************************************************************************************
+    ********************************************************************************************************************************
+    */
+    
     //add event listeners to the dial buttons
     var initCallElems = document.getElementsByClassName('initCall');