This move was planned from the beginning; Widget::CachePaintMode was a
backport of the same feature in Qt 4.4. OK'ed by aseigo after post on
panel-devel. I've left CachePaintMode in there (it simply redirects to
CacheMode); I don't know if it's OK to remove these APIs or not (and
it's not monday anyway).
svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=775198