refactor rename examples --> demo

pom.xml

xchart-demo/pom.xml

...t-demo/src/main/java/com/xeiam/xchart/demo/ChartInfo.java

...-demo/src/main/java/com/xeiam/xchart/demo/XChartDemo.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example1.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example2.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example3.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example4.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example5.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example6.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example7.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example8.java

.../src/main/java/com/xeiam/xchart/demo/charts/Example9.java

.../main/java/com/xeiam/xchart/demo/charts/ExampleChart.java

...demo/src/main/java/com/xeiam/xchart/example/Example0.java

...demo/src/main/java/com/xeiam/xchart/example/Example1.java

...demo/src/main/java/com/xeiam/xchart/example/Example2.java

xchart/pom.xml