added Swing Helper

dist/xchart-1.0.0.jar

src/com/xeiam/swing/ButtonDemo.java

src/com/xeiam/swing/SwingHelper.java

src/com/xeiam/xcharts/example/SwingChart.java

src/com/xeiam/xcharts/example/SwingChart2.java

src/com/xeiam/xcharts/example/SwingChart3.java

src/com/xeiam/xcharts/example/SwingChart4.java

src/com/xeiam/xcharts/example/SwingChart5.java