title: Run Firefox in headless mode using Protractor config
body: <p>I have this in my Protractor config:</p>
  
  <pre><code>  multiCapabilities: [
  
      {
        browserName: 'firefox',
        firefoxOptions: {
          args: ['-headless']
        },
        'moz:firefoxOptions': {
          args: ['-headless']
        }
      }
  
    ]
  </code></pre>
  
  <p>unfortunately, when I launch Protractor, Firefox still runs in a headful mode. How to the heck do I tell Firefox to as headless?</p>
  
  <p>I know that at the command line, the <code>-headless</code> option should work so.</p>