An extra widget has been added to arboreal, to support Mac finder-like selector.
The code is coming from: http://alistapart.com/articles/complexdynamiclists and is quite unintrusive.

Some javascript and css needs to be available. It has been copied into the skin as: finder.js and finder.css
A bunch of graphics is needs, has also been put into the arboreal skin.

Some modification had to be made to finder.js to register it with the plone 'onload' machinery and to accomodate the use
of checkboxes.

The js and css files are registered with the portal_css and portal_javascript tool at quickinstall time.

A widget has been added to 'abr_multiselection_widget', a format of type 'finder' can now be used.

A macro has been added to 'abr_tree_view_macro', that can render a finder view, useful for searchform. 
However, this one is a bit specific.
It expects a recursive list of hashes: [{'path': '/arbo-path', 'title': 'a title', 'subs: [ <the recursive list> ]}]


