title: Disable/Enable Grouping in ui-grid
body: <p>I have a ui-grid whose first column is:</p>
  
  <pre><code>  columnDefs : [$scope.getGroupIdColumn(),
                  $scope.getKlasCodeColumn(),
                  $scope.getKlasNummerColumn(),
                  $scope.getNaamColumn()
              ]
  </code></pre>
  
  <p>where <code>getGroupIdColumn</code> is: </p>
  
  <pre><code>    $scope.getGroupIdColumn = function () {
          var result = new Object();
          result["name"] = 'GroupID';
          result["visible"] = false;
          result["type"] = 'number';
          if ($scope.groupingEnabled) {
              console.log("komt toch: " + $scope.speedDial.grouping);
              var grObj = new Object();
              grObj["groupPriority"] = 0;
              result["grouping"] = grObj;
              return result;
          }
          return result;
      }
  </code></pre>
  
  <p>Other column definitions are also like this.</p>
  
  <p>If <code>groupingEnabled</code> is true, i have grouping. If false, without grouping. Until here, it works as excepted.</p>
  
  <p>BUT</p>
  
  <p>If i redefine that column, or even all the grid-options, it remains same as it is. Thus, if i have a grid with grouping and i redefine all grid options, i have still grid with grouping.</p>
  
  <p>What should be done?</p>
  
  <p><em>PS: gridApi.core.refresh(), $evalAsync().. are tried and no any improvement.</em></p>