Adding initial support for two new datasets: XYDataset and XYZDataset. New example charts for XYDataset are ScatterPlot and XYLineChart and for XYZDataset it is BubbleChart.
Adding some default margin to BubbleChart and some default gridlines visible for scatter plot with CategoryDataset.
Unifying license text in package org.jfree.data.xml. Making XYDataset work in addition to previously XYZDataset.
Adding more XYDataset chart types: XYAreaChart, XYBarChart, Making XYDataset work in addition to previously XYZDataset.
Commenting out System.out.println statements in XYZItemHandler.java.
Adding new configuration options for CategoryAxis and NumberAxis: foregroundAlpha, rangeLowerMargin, rangeUpperMargin, domainLowerMargin (NumberAxis only), domainUpperMargin (NumberAxis only), domainLowerBound (NumberAxis only), domainUpperBound (NumberAxis only), rangeAutoRangeIncludesZero, domainAutoRangeIncludesZero (NumberAxis only), rangeZeroBaselineVisible, domainZeroBaselineVisible (NumberAxis only), rangeIntegerTickUnits, domainIntegerTickUnits (NumberAxis only), rangeGridlinesVisible, domainGridlinesVisible, and for ScatterPlot: dotHeight, dotWidth.
Merge pull request #8 from ljo/develop

Adding support for new XYDataset and XYZDataset charts.