catch up with rename

Filename and envvars were updated, but platform and URL weren't.

Author: chadwhitacre

examples/gratipay_send_tip.php

@@ -9,20 +9,20 @@
 $data = array(
     array(
         'username' => 'user' . mt_rand(),
-        'platform' => 'gittip',
+        'platform' => 'gratipay',
         'amount' =>  '0.02',
     ),
     array(
         'username' => 'user' . mt_rand(),
-        'platform' => 'gittip',
+        'platform' => 'gratipay',
         'amount' =>  '0.02',
     ),
 );
 
 $curl = new Curl();
 $curl->setHeader('Content-Type', 'application/json');
 $curl->setBasicAuthentication(GRATIPAY_API_KEY);
-$curl->post('https://www.gittip.com/' . GRATIPAY_USERNAME . '/tips.json', json_encode($data));
+$curl->post('https://gratipay.com/' . GRATIPAY_USERNAME . '/tips.json', json_encode($data));
 
 foreach ($curl->response as $tip) {
     echo $tip->amount . ' given to ' . $tip->username . '.' . "\n";