title: WebStorm error message - use esversion 6
body: <p>WebStorm is showing the following error message:</p>
  
  <p><code>JSHint: 'let' is available in ES6 (use 'esversion': 6) ...</code></p>
  
  <p>In the Preferences -> Languages &amp; Framework -> JavaScript menu I've selected the <code>ECMAScript 6</code> option and my <code>.jshintrc</code> file does contain the <code>"esversion": 6,</code> line.</p>
  
  <p>I've tried the two most recent versions of the app (which are now 2016.3.6 and 2017.1.2) but to no avail.</p>
  
  <p>I've also deleted the files in <code>~/Library/Application Support/WebStormXX</code> and
  <code>~/Library/Preferences/WebStormXX</code> but nothing seems to have changed. </p>
  
  <p>I'm using OS X 10.10.5.</p>