This basically removes the "adv" library, even though it's still
preserved for compatibility with user make/project files referring to
it.
It is done because the distinction between "adv" and "core" was never
really clear (e.g. why wxTreeCtrl was in core but wxTreeListCtrl in
adv?) and it prevented some core classes from using adv ones.
This is a simple high level helper combining an arbitrary control showing
multiple items with the buttons allowing to add items to and remove items from
this control, but using the buttons and the layout appropriate for the current
platform.
Add the implementation itself, an example of using it to the dialogs sample
and the documentation.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78462 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
