The charting system was written before the ITabular interface was introduced, so it depends on having an adapter class to understand the different types of input datasets.
Now we have an ITabular interface, where any dataset that has data which can be interpreted in a tabular format, can now be accessed using the same interface.

We should add a charting adapter to use the ITabular interface, so other new dataset types, which are tabular but don't have chart data adapters, can be used.