Ported KPrinter to Qt4's painting system.
The main change is KPrinter's interception of QPainter::begin, QPainter::end
before they are passed to QPrint*. Before, QPaintDevice::cmd was used - but
since this no longer exists, KPrinter uses its own QPaintEngine and passes on
all the calls to QPrintEngine*. This is probably not the most elegant solution,
but it works.