XYLegendWidget Suboptimal Sizing #64

Hello,

XYLegendWidget

Issue: If you have, say, 5 SeriesBundle with 2 legendenabled==false it
shows 3 legends and 2 empty cells, which is wasted space.

Row 191
int nWithoutLegend = plot.getRegistry().getSeriesList().size() -
plot.getRegistry().getLegendEnabledItems().size();
seriesCount -= nWithoutLegend;

as quick fix works for me.

Thanks