title: Creating restify createJsonClient
body: <p>Trying to write some mocha tests for my restify server.  Some of the services require an Authorization header.</p>
  
  <p>I am trying to set it this way:</p>
  
  <pre><code>var client = restify.createJsonClient({
    version: '1.0.0',
    url: 'http://localhost:9000',
    headers: {Authorization:'Bearer ' + global.access_token}
  
  });
  </code></pre>
  
  <p>but inspecting the request headers shows its not getting set, and my test is failing because of invalid credentials.</p>
  
  <p>reading here, i believe i have the headers option.</p>
  
  <p><a href="http://restifyjs.com/#jsonclient" rel="nofollow">http://restifyjs.com/#jsonclient</a></p>
  
  <p>global.access_token is being set correctly.</p>
  
  <p>Can someone help with some options on how to set that header?</p>
  
  <p>Thanks</p>