* don't grab the data until actually shown
* show the right size and position when we are showing the tip
* allow the tooltip to figure out it's size with the help of the widget (it knows when to do this, the widget only knows how)
* don't show the tip on every item's mouse over, respect the small timeout
* only create a ToolTipData struct for those items that actually use it (memory savings as well as makes the check for showing the tip a lot simpler)
svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=771314