updated example code to show adding series on List<Integer> etc…

...n/java/com/xeiam/xchart/demo/charts/area/AreaChart02.java

...ain/java/com/xeiam/xchart/demo/charts/bar/BarChart02.java

...n/java/com/xeiam/xchart/demo/charts/date/DateChart01.java

...n/java/com/xeiam/xchart/demo/charts/date/DateChart02.java

...n/java/com/xeiam/xchart/demo/charts/date/DateChart03.java

...n/java/com/xeiam/xchart/demo/charts/date/DateChart04.java

...n/java/com/xeiam/xchart/demo/charts/date/DateChart05.java

...n/java/com/xeiam/xchart/demo/charts/date/DateChart06.java

...n/java/com/xeiam/xchart/demo/charts/date/DateChart07.java

...n/java/com/xeiam/xchart/demo/charts/line/LineChart01.java

...n/java/com/xeiam/xchart/demo/charts/line/LineChart02.java

...n/java/com/xeiam/xchart/demo/charts/line/LineChart03.java

...n/java/com/xeiam/xchart/demo/charts/line/LineChart06.java

.../com/xeiam/xchart/demo/charts/scatter/ScatterChart01.java

.../com/xeiam/xchart/demo/charts/scatter/ScatterChart02.java

.../com/xeiam/xchart/demo/charts/scatter/ScatterChart04.java

...java/com/xeiam/xchart/demo/charts/theme/ThemeChart03.java

xchart/src/main/java/com/xeiam/xchart/Chart.java