title: Kendo grid filter does not work with columns with special characters
body: <p>I am using Kendo UI Grid to display data. I am generating gird with dynamic column names so, spaces, numbers and special characters(_) are possible as column field. To achieve this, I have to pass column name like <code>['column_1']</code>. This works proper for displaying data, but in this case column filter is not working specific for date columns. Below is example code.</p>
  
  <pre><code>  {
      field: "['Column_1']",
      title: "Column 1",
      format: "{0:MM/dd/yyyy HH:mm tt}",
      filterable: {
        ui: "datetimepicker"
      }
    }
  </code></pre>
  
  <p>This will display grid header and data proper but at the time of filtering date column, it gives below error.</p>
  
  <pre><code>getTime is not a function
  </code></pre>