Using the Plasma ToolTipManager to provide the same tooltips as in the tasks applet.
Currently only icons and title are displayed for tabs. Preview will be added as soon
as the tab's WId is exported by KWin core.
Unfortunately the tooltips are missing translucency.
FEATURE: 228436
FIXED-IN: 4.6.0

svn path=/trunk/KDE/kdebase/workspace/; revision=1188226