moves series map, renamed ChartPainter ==> ChartInternal

xchart/src/main/java/org/knowm/xchart/Chart.java

...c/main/java/org/knowm/xchart/internal/chartpart/Axis.java

...in/java/org/knowm/xchart/internal/chartpart/AxisPair.java

...in/java/org/knowm/xchart/internal/chartpart/AxisTick.java

...t/internal/chartpart/AxisTickCategoryChartCalculator.java

...a/org/knowm/xchart/internal/chartpart/AxisTickLabels.java

...va/org/knowm/xchart/internal/chartpart/AxisTickMarks.java

...n/java/org/knowm/xchart/internal/chartpart/AxisTitle.java

...va/org/knowm/xchart/internal/chartpart/ChartInternal.java

...n/java/org/knowm/xchart/internal/chartpart/ChartPart.java

.../java/org/knowm/xchart/internal/chartpart/ChartTitle.java

...main/java/org/knowm/xchart/internal/chartpart/Legend.java

...c/main/java/org/knowm/xchart/internal/chartpart/Plot.java

...java/org/knowm/xchart/internal/chartpart/PlotContent.java

...chart/internal/chartpart/PlotContentCategoricalChart.java

.../xchart/internal/chartpart/PlotContentNumericalChart.java

...java/org/knowm/xchart/internal/chartpart/PlotSurface.java