title: Export plugin broken in Grails 2.3.7
body: <p>We recently encountered a problem with the excel-export plugin with Grails 2.3.7.
  We've tried both 0.1.4 and 0.1.6, and can recreate the issue in a couple of lines.</p>
  
  <pre><code>import pl.touk.excel.export.WebXlsxExporter
  
  def headers = ['Name', 'Description']
  
  def withProperties = ['name', 'description']
  
  List&lt;Integer&gt; products = new ArrayList&lt;Integer&gt;()
  
  new WebXlsxExporter().with {
      fillHeader(headers)
      add(products, withProperties)
      save()
  }
  </code></pre>
  
  <p>This throws:</p>
  
  <blockquote>
    <p>No signature of method: fillHeader () is applicable for argument types: (java.util.ArrayList) values: [[Name, Description]]</p>
  </blockquote>
  
  <p>This was working fine in Grails 2.0.3 with excel-export 0.1.4</p>
  
  <p>Any ideas?</p>