After switching everything to drawing using bare QPainter, a lot
of ViewPainter-based stuff became unused and basically obsolete,
including the ViewPainter itself.
1. Wire label bounding box is determined correctly. Introduced
WireLabel::getLableBounding() method. It is used for selected labels
and Schematic::sizeOfAll() method.
2. Corrected wire size determination for selected wires.
When a WireLabel was highlighted the current font was set to be
Qt::DemiBold and not restored when exiting the paint() function;
as a side effect other Elements using the same ViewPainter had
their text drawn also in DemiBold.
In Qt4 the actual font size depends on the device that will actually
paint the font. To avoid to explicitly ask the painter to compute
the font size we can use QFontMetrics::QFontMetrics(font, 0) to
always obtain the correct screen metric (behavior similar to the Qt3
default). All istances of QFontMetrics have now been so modified.
