title: Custom Sorting in Angulargrid - sort case insensitve
body: <p>I am using ag-grid for generating some tables. So far it has been great. But I am experiencing some difficulty in sorting because my table has some data which are in lowercase and I want my sorting function to ignore the case and sort them just has case sensitive.</p>
  
  <p>The two features that can do this job are cellRenderer and sort function.</p>
  
  <p><em>cellRenderer function:</em></p>
  
  <pre><code>cellRenderer: function(params) {
      if (params.value=='Police') {
          return 'POLICE';
      } else {
          return params.value.toUpperCase();
      }
  }
  </code></pre>
  
  <p><em>sorting function:</em></p>
  
  <pre><code>$scope.sortByAthleteAsc = function() {
      var sort = [
          {field: 'athlete', sort: 'asc'}
      ];
      $scope.gridOptions.api.setSortModel(sort);
  };
  </code></pre>
  
  <p>These are the two examples provided. How can I connect these two functions to produce my table case insensitive sorting?</p>