Classgraphic

* added 2D clustering visualization
* defaults to Voronoi tessalation
* optional Delauney triangulation

* added binary classification notebook example
* fixed issue with non dataframe binary classification

The previous version was a first step to doing a public release. This
release added:
* documented
* updated the code to be in line with plotly 5.x

It was released to [github](https://github.com/dionresearch/classgraphic) and pypy.

* First private release

Origins

Inspired by Dion Research LLC Internal EDA/anomaly and end to end data science platform.
A dozen charts and tables were initially designed to provide better diagnostic reporting.
Some can also be used for exploratory or explanatory purposes.

See:
https://blog.dionresearch.com/2019/10/visualizations-explanatory-exploratory.html