title: datatable column filtering not working
body: <p>I have been trying to figure out why my table won't filter. Data is being pulled and is populating the table. In addition, input filter boxes are present in the table footer, however inputting characters in the filter boxes is not doing anything. The 'Processing' signal is displayed very shortly after inputting, but no filtering is actually taking place. The code is quite simple. I am not sure what I'm missing. I am using this same functionality on other pages with tables and there are no issues, the only difference is that this table is using Ajax source. So I'm thinking that may have something to do with it. I've added bProcessing because I thought that was the reason, and bFilter as well, but still no filtering is taking place.</p>
  
  <pre><code>$(document).ready(function() {
      $('#MyTable').dataTable({
          bJQueryUI : true,
          "bServerSide" : true,
          "bProcessing" : true,
          "sAjaxSource" : "../../myfile.json",
          "bFilter": true,
          "bInfo": true,
          "fnServerParams":function(aoData){
              aoData.push({"name":"userid", "value":userid})
          },
          "aoColumns": [  
              {"mDataProp": "userLastName",
              "bSortable":true,
              "bSearchable" : true}, 
              {"mDataProp": "userFirstName",
              "bSortable":true,
              "bSearchable" : true},
              {"sWidth" : "750px",
              "mDataProp": "status",
              "bSortable" : false,
              "bSearchable" : true}
          ]
      })
      .columnFilter({
              aoColumns: [
                  {type:"text"},
                  {type:"text"},
                  {type:"text"}
              ]
       });
  });
  </code></pre>