Improve checkbox click handling support for grids

i.e. let custom use define click handlers

tailbone/templates/grids/buefy.mako

@@ -131,7 +131,15 @@
        :row-class="getRowClass"
 
        :checkable="checkable"
+       % if grid.checkboxes:
        :checked-rows.sync="checkedRows"
+       % endif
+       % if grid.check_handler:
+       @check="${grid.check_handler}"
+       % endif
+       % if grid.check_all_handler:
+       @check-all="${grid.check_all_handler}"
+       % endif
        ## TODO: definitely will be wanting this...
        ## :is-row-checkable=""
 
@@ -228,18 +236,20 @@
 
 <script type="text/javascript">
 
+  let TailboneGridCurrentData = ${json.dumps(grid_data['data'])|n}
+
   let TailboneGridData = {
       loading: false,
-      checkedRows: [],
       selectedFilter: null,
       ajaxDataUrl: ${json.dumps(grid.ajax_data_url)|n},
 
-      data: ${json.dumps(grid_data['data'])|n},
+      data: TailboneGridCurrentData,
       rowStatusMap: ${json.dumps(grid_data['row_status_map'])|n},
 
       checkable: ${json.dumps(grid.checkboxes)|n},
-      ## TODO: should be dumping json from server here?
-      ## checkedRows: [],
+      % if grid.checkboxes:
+      checkedRows: ${grid_data['checked_rows_code']|n},
+      % endif
 
       paginated: ${json.dumps(grid.pageable)|n},
       total: ${len(grid_data['data']) if static_data else grid_data['total_items']},