Added the ability to build interactive, hierarchical bubble charts.
A 'bubble' chart helps visualize hierarchical data as circles that have an area proportional to the value of the record. Inside parent records, child records can be nested.
The visualization depth of the hierarchical data can be easily adjusted.
The appearance of the chart can be changed in code or directly in the chart style editor.
The library also contains predefined color palettes.
Improved MainDemo interface and added new planets dataset.