Issue MicahCarrick#3 - Added force_ssl_v3 parameter for cURL using Gn…

…uTLS.

ipnlistener.php

@@ -23,6 +23,14 @@ class IpnListener {
      */
     public $use_curl = true;     
 
+    /**
+     *  If true, explicitly sets cURL to use SSL version 3. Use this if cURL
+     *  is compiled with GnuTLS SSL.
+     *
+     *  @var boolean
+     */
+    public $force_ssl_v3 = false;     
+
     /**
      *  If true, an SSL secure connection (port 443) is used for the post back 
      *  as recommended by PayPal. If false, a standard HTTP (port 80) connection
@@ -86,6 +94,10 @@ protected function curlPost($encoded_data) {
         curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
         curl_setopt($ch, CURLOPT_HEADER, true);
 
+        if ($this->force_ssl_v3) {
+            curl_setopt($ch, CURLOPT_SSLVERSION, 3);
+        }
+
         $this->response = curl_exec($ch);
         $this->response_status = strval(curl_getinfo($ch, CURLINFO_HTTP_CODE));