Several fixes for removing/readding controls to the toolbar:

Several fixes for removing/readding controls to the toolbar:

1. Don't destroy the control in wxToolBar::RemoveTool() as this prevents
   it from being added back with is the purpose of using RemoveTool() rather
   than DeleteTool().

2. Call wxToolBarTool::Attach/Detach() from the base code, not just from wxMSW
   and wxMac (wasn't called by wxGTK at all).

3. Allow adding back the removed control tool in wxGTK.

4. Add test for removing/adding back a control tool to the sample.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@52840 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775