The abstract class
defines the functionality that any chart implementation is expected so support.
Most prominently, this includes the possibility to add edges, to modify the appearance of edges and segments,
and to define a dependency hierarchy on the chart edges, e.g. for highlighting the components of edges
which represent a combination of smaller edges.
Any class implementing
KahinaChart can be visualized
KahinaMemChart is the reference chart implementation which implements
the functionality in a straightforward manner. It is not useful for more than medium-sized charts
because the entire data is stored in memory (hence the name).