Add back the rendering of text shadows for pattern labels

Add back the rendering of text shadows for pattern labels. If some
design does not want shadows beneath the text it's always possible to
set the CSS property qproperty-textShadowColor to something completely
transparent.

src/core/Track.cpp

@@ -663,8 +663,11 @@ void TrackContentObjectView::paintTextLabel(QString const & text, QPainter & pai
 
 	painter.fillRect(QRect(0, 0, width(), fontMetrics.height() + 2 * textTop), textBackgroundColor());
 
+	int const finalTextTop = textTop + fontMetrics.ascent();
+	painter.setPen(textShadowColor());
+	painter.drawText( textLeft + 1, finalTextTop + 1, elidedPatternName );
 	painter.setPen( textColor() );
-	painter.drawText( textLeft, textTop + fontMetrics.ascent(), elidedPatternName );
+	painter.drawText( textLeft, finalTextTop, elidedPatternName );
 }
 
 /*! \brief Handle a mouse press on this trackContentObjectView.