Adapt to grid activatable editors

Since wxWidgets uses an activable editor for wxGridCellBoolEditor,
wxGridEditorCreatedEvent is no longer emitted for such a column.

See https://trac.wxwidgets.org/ticket/19071

Using wxEVT_GRID_CELL_CHANGED to clear all checkboxes in preferred
column, instead of relying on the created editor pointer which can no
longer be referenced.

L7/nbproject/private/private.xml

@@ -6,6 +6,10 @@
     </data>
     <editor-bookmarks xmlns="http://www.netbeans.org/ns/editor-bookmarks/2" lastBookmarkId="0"/>
     <open-files xmlns="http://www.netbeans.org/ns/projectui-open-files/2">
-        <group/>
+        <group>
+            <file>file:/home/user/Documents/published/L7/L7/LBoundGrid.cpp</file>
+            <file>file:/home/user/Documents/published/L7/L7/special/BaseGridPicker.h</file>
+            <file>file:/home/user/Documents/published/L7/L7/special/BaseGridPicker.cpp</file>
+        </group>
     </open-files>
 </project-private>