add the client mode to the challenge

src/PIChallenge.php

@@ -13,6 +13,9 @@ class PIChallenge
     /* @var string Image data for this challenge. */
     public $image = "";
 
+    /* @var string Client mode matching this challenge. */
+    public $clientMode = "";
+
     /* @var string TransactionId to reference this challenge in later requests. */
     public $transactionID = "";
 

src/PIResponse.php

@@ -156,6 +156,7 @@ class PIResponse
                 $tmp->message = $challenge['message'];
                 $tmp->serial = $challenge['serial'];
                 $tmp->type = $challenge['type'];
+                $tmp->clientMode = $challenge['client_mode'];
                 if (isset($challenge['image']))
                 {
                     $tmp->image = $challenge['image'];