title: global_merge_vars not working
body: <p>I'm sending a template email from Mandrill API like this:</p>
  
  <pre><code>{
     "key":"xxxyyyzzz",
     "template_name":"coupon-purchased",
     "template_content":[
     ],
     "message":{
        "to":[{"email":"xxx@yyy.com"}]
     },
     "merge":true,
     "global_merge_vars":[
        {
           "name":"FNAME",
           "content":"Your name"
        },
        {
           "name":"FGYMNAME",
           "content":"Your gym"
        }
     ],
     "merge_vars":[
     {
        "rcpt": "xxx@yyy.com",
        "vars":[
           {
              "name":"FNAME",
              "content":"Your name"
           },
           {
              "name":"FGYMNAME",
              "content":"Your gym"
           }
        ]
     }]
  }
  </code></pre>
  
  <p>As a POST message to this URL: <a href="https://mandrillapp.com/api/1.0/messages/send-template.json" rel="nofollow">https://mandrillapp.com/api/1.0/messages/send-template.json</a></p>
  
  <p>I've tried with some HTML document, but finally I'm just using the following as template:</p>
  
  <pre><code>*|FNAME|* and *|FGYMNAME|*
  </code></pre>
  
  <p>But still not working. Those variables are not exchanged with the values sent in global_merge_vars.</p>
  
  <p>Also, I've tried to remove <code>merge_vars</code> and <code>merge</code> properties from JSON, not working neither.</p>
  
  <p>Any clues about it?</p>
  
  <p>Thanks!</p>