W7 Tab thumbnails in dolphin.

Review Request #102758 - Created Oct. 3, 2011 and discarded - Latest diff uploaded

Andrius da Costa Ribas
kde-baseapps, kdeaccessibility, kdewin, plasma
ppenz, sengels
Add Windows 7 tab thumbnails feature to dolphin.
Mostly based on the example from <http://nicug.blogspot.com/2011/03/windows-7-taskbar-extensions-in-qt-tab.html>.

An icon representation is used instead of actual thumbnails ( please agree that those microscopic previews are not useful at all ;] ). Changing an icon when url changes is also easier than checking all the time whether something inside the window has been changed. Using icons is a lot more KDE-ish and therefore more beautiful and user-friendly than the default Windows behavior ;).

"win7utils.h" and "win7utils.cpp" are from <https://github.com/xfreebird/blogstuff/tree/master/qt/thumbnailtabs_example1> with few adaptations.
Tested using MSVC 2010 32 bit, in a Windows 7 64 bit machine.

May need testing:
- Compiling under mingw-w32 and mingw-w64
- Using Windows Vista or below to ensure there are no side-efects on a box without this feature.
- Using Windows 8 (I don't know much about its bugs^H^H^H^Hfeatures ;] )

Known problems:
- There is no way to know if KTabBar got a tab reordered, so the "thumbnails" won't be reordered, but their reference is still correct
- Undefined behavior when dolphin gets unresponsive [e.g.: because of a defective kioslave], most of the code assume dolphin is okay [e.g.: QPixmap::grabWidget won't work in a frozen window].