title: Does Mocha ignore --harmony option in mocha.opts?
body: <p>In my test directory, I have a file <code>mocha.opts</code> containing the following:</p>
  
  <pre><code>--harmony
  --recursive
  --growl
  --reporter spec
  --require should
  </code></pre>
  
  <p>When I run <code>mocha</code>, I get the following error:</p>
  
  <pre><code>/project/server/utilities/encryption.js:3
  const
  ^^^^^
  SyntaxError: Use of const in strict mode.
  </code></pre>
  
  <p>This is, of course, because my use of <code>const</code> requires ES6 Harmony.  When I run <code>mocha --harmony</code>, my tests execute just fine.  And the other entries in my <code>mocha.opts</code> file work as expected.</p>
  
  <p>Does the <code>mocha.opts</code> file ignore the <code>--harmony</code> argument for some reason?  Or am I doing it wrong?  The Mocha docs don't elaborate and I haven't been able to find the answer here or anywhere else.</p>