digiKam from trunk (KDE4) : add thumbbar behind preview area from AlbumGUI when preview mode is used (F3).

Icon view filter available to status bar and TagFilters still suitable to change thumbbar contents in live.

Thumbbar items can display Rating of pictures. More information about thumbbar items are available using pop-up tool tips is you enable this option in config dialog.

A fresh screenshot is available at these url:

- with Digikasa color theme : <a href="/issues/2008-03-23/files/thumbbar4albumgui.png">http://digikam3rdparty.free.fr/Screenshots/thumbbar4albumgui.png</a>;
- with Desert color theme : <a href="/issues/2008-03-23/files/thumbbarwithpreviewmode.png">http://digikam3rdparty.free.fr/Screenshots/thumbbarwithpreviewmode.png</a>;