fix: grid with Grouping, Row Select All shouldn't include grouping ro…

…ws (mleibman#635)

- if we use Row Selection with a grid that also has Grouping/Draggable Grouping, clicking on the "Select All" button would also include grouping rows and when calling DataView `getAllSelectedIds()` it would includes some `undefined` Ids which were found to be the grouping rows. So we should fix the issue at the source, which is to NOT include the grouping rows.

plugins/slick.checkboxselectcolumn.js

@@ -221,8 +221,8 @@
           var rows = [];
           for (var i = 0; i < _grid.getDataLength(); i++) {
             // Get the row and check it's a selectable row before pushing it onto the stack
-            var rowItem = _grid.getDataItem(i);            
-            if (checkSelectableOverride(i, rowItem, _grid)) {
+            var rowItem = _grid.getDataItem(i);
+            if (!rowItem.__group && !rowItem.__groupTotals && checkSelectableOverride(i, rowItem, _grid)) {
               rows.push(i);
             }
           }