title: Kendo UI Grid column headerTemplate function does not get access to the column definition
body: <p>I'm trying to use the <a href="http://docs.telerik.com/kendo-ui/api/web/grid#configuration-columns.headerTemplate" rel="noreferrer">columns.headerTemplate</a> feature of a <a href="http://docs.telerik.com/kendo-ui/getting-started/web/grid/walkthrough" rel="noreferrer">Kendo UI Grid</a> to customise the column header. You use this feature as shown below and as demonstrated by <a href="http://dojo.telerik.com/@martinho/uHAyE/2" rel="noreferrer">this example I created</a>. Normally when using <a href="http://docs.telerik.com/kendo-ui/api/framework/kendo#methods-template" rel="noreferrer">Kendo UI templates</a>, the widget will pass the entity into template function so you can use the various properties to customise the html to be rendered. </p>
  
  <p>Debugging the Kendo UI Grid code I can see that in the <code>_headerCellText</code> method the call to the template function passes in an empty object rather than the column even though column object is in scope. </p>
  
  <p><code>text = kendo.template(template, settings)({});</code></p>
  
  <p>Is there another approach I can take before resorting to custom column header templates for each column or worse - jQuery manipulation of the widget rendered DOM?</p>
  
  <p>Is there a good reason for deviating from the common template pattern in the framework for this use case?</p>
  
  <pre><code>// Example kendoGrid use of column.headerTemplate
  var templateFunction = function(shouldBeColumn) {
      // shouldBeColumn is an empty object rather than the column object
      return "Useless object:" + kendo.stringify(shouldBeColumn);
    };
  
  $("#grid").kendoGrid({
      dataSource: {
          data: products,
          pageSize: 20
      },
      height: 550,
      scrollable: true,
      columns: [
        { field: "ProductName", title: "Product Name" },
        { field: "UnitPrice", title: "Unit Price", headerTemplate: plainTemplate },
        { field: "UnitsInStock", title: "Units In Stock", headerTemplate: templateFunction }
      ]
  });
  </code></pre>