title: paypal sdk 'Class 'PayPal\Rest\ApiContext' not found'
body: <p>I'm trying to implement paypal api sdk using this code</p>
  
  <pre><code>require('vendor/autoload.php');
  use PayPal\Rest\ApiContext;
  use PayPal\Auth\OAuthTokenCredential;
  
  $api = new ApiContext(
   new OAuthTokenCredential(
      'client id',
      'secret'
   )
  );
  
  $api-&gt;setConfig([
   'mode'=&gt;'sandbox',
   'http.ConnectionTimeOut'=&gt;30,
   'log.LogEnabled'=&gt;false,
   'log.FileName'=&gt;'',
   'log.LogLevel'=&gt;'FINE',
   'validation.level'=&gt;'log'
  ]);
  </code></pre>
  
  <p>The Rest and Auth folders are subfolders of PayPal folder which exists inside the vendor folder. But I get this error "Class 'PayPal\Rest\ApiContext' not found"</p>