date charts improved drastically

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

.../chartpart/axistickcalculator/DateAxisTickCalculator.java

...c/test/java/com/xeiam/xchart/unit/ValueFormatterTest.java