remove non-filled bar chart style, rename some methods

etc/XChart_Chart_Customization.png

...n/java/org/knowm/xchart/demo/charts/area/AreaChart01.java

...n/java/org/knowm/xchart/demo/charts/area/AreaChart02.java

...va/org/knowm/xchart/demo/charts/area/AreaLineChart03.java

...ain/java/org/knowm/xchart/demo/charts/bar/BarChart02.java

...n/java/org/knowm/xchart/demo/charts/date/DateChart02.java

...n/java/org/knowm/xchart/demo/charts/line/LineChart07.java

.../org/knowm/xchart/demo/charts/scatter/ScatterChart01.java

.../org/knowm/xchart/demo/charts/scatter/ScatterChart02.java

...java/org/knowm/xchart/demo/charts/stick/StickChart01.java

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

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

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

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

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

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

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

...main/java/org/knowm/xchart/internal/Series_AxesChart.java

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

.../xchart/internal/chartpart/AxisTickCalculator_Number.java