title: Uncss Ignore option isn't working
body: <p>I'm trying remove the css with <a href="https://github.com/addyosmani/grunt-uncss" rel="nofollow">uncss</a> but it's removing all the styles no matter if they are listed on the <strong>ignore</strong> array.</p>
  
  <p>The 2 files that I want to compare are just the index and the app.min.js which contains all the templates embedded in the javascript as strings, which are configured using <a href="https://docs.angularjs.org/api/ng/service/$templateCache" rel="nofollow">$templateCache</a></p>
  
  <p>take a look to the grunt task maybe there is something obvious that I'm missing:</p>
  
  <pre><code>uncss:{
      production: {
          options: {
              ignore: ['.someclass', '.someclass', '.someclass','.etc_etc_class'],
              stylesheets:['app.min.css']
          },
          files: {
              'dist/app.min.css':['dist/index.html','dist/app.min.js']
          }        
      }
  }
  </code></pre>
  
  <p>any comment will be more than welcome!</p>