add sample bar chart 10, fix broken y aix tick calculator for bar charts

...ain/java/org/knowm/xchart/demo/charts/bar/BarChart09.java

...ain/java/org/knowm/xchart/demo/charts/bar/BarChart10.java

...g/knowm/xchart/internal/chartpart/AxisTickCalculator.java

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

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

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