Add QChart to Python Chart (4b of 5)

Stack charts now when set as an option, in which case all
data series are given their own plot.

Or alternatively, where data series have different x-axis
names, they get a plot for each x-axis.

Need to fixup a) minimum height as can get squashed and
b) scroll area needed as well as c) layout direction.

src/Charts/GenericPlot.cpp

@@ -17,6 +17,7 @@
  */
 
 #include "GenericPlot.h"
+#include "GenericChart.h"
 
 #include "Colors.h"
 #include "TabView.h"
@@ -208,7 +209,7 @@ GenericPlot::setSeriesVisible(QString name, bool visible)
 
 // annotations
 void
-GenericPlot::addAnnotation(AnnotationType type, QAbstractSeries*series, double value)
+GenericPlot::addAnnotation(AnnotationType , QAbstractSeries*series, double value)
 {
     fprintf(stderr, "add annotation line: for %s at value %f\n", series->name().toStdString().c_str(), value);
     fflush(stderr);