title: how to access table itself from dtOptions in angularJS-datatables
body: <p>I'm tring to have a csv download button and need to exclude a couple of columns from table.</p>
  
  <p>I've found a exportOptions defines which columns should be exported.
  this option comes from jQuery datatalbles and table.column() method is likely to be used to select columns.</p>
  
  <p>now I need to select certain columns, but I couldn't find out how with angular-datatables way.</p>
  
  <p>anyone knows solution?</p>
  
  <pre><code>    &lt;table dt-options="dtOptions" dt-column-defs="dtColumnDef"&gt;
          &lt;thead&gt;
              &lt;tr&gt;
                  &lt;th&gt;hoo&lt;/th&gt;
                  &lt;th&gt;hoo&lt;/th&gt;
              &lt;/tr&gt;
          &lt;/thead&gt;
          &lt;tbody&gt;
              &lt;tr&gt;
                  &lt;td&gt;hoo&lt;/td&gt;
                  &lt;td&gt;hoo&lt;/td&gt;
              &lt;/tr&gt;
          &lt;/tbody&gt;
      &lt;/table&gt;
  
  
  
  &lt;script&gt;
      // here is inside my controller
  
      $scope.dtOptions = DTOptionsBuilder
      .newOptions()
      .withDOM('tB')
      .withButtons([
      {
          text: 'download csv',
          extend: 'csv',
          exportOptions:
          {
              // columns: I neet to select certain columns here
              // wiht method like "table.columns(0)" mentioned in jQuery datatables document
              // but I don't know how in angular-datatables
          }
      }]);
  &lt;/script&gt;
  </code></pre>
  
  <p>I use angular-way to render table.</p>