Nx3d

- added scipy as a dependency to handle sparse solvers for positions when there are > 500 nodes (see networkx spring layout source)
- moved issue tracking from text to github issues
- added a variety of "markers" for nodes (rather than just the icosahedron)
- refactored examples to handle n>1 examples
- working 2d grid game of life example
- docs got a full makeover
- implemented digraph support

Sun Sep 19 2022

- no longer deepcopying the graph passed to the plotting function
- using nx graph attributes to track desired 3d model state
- added CI and tests

- implemented edge attribute interface for 'label' and 'color'

- implemented state transition function so now dynamic graphs are renderable
- implemented graph diffusion example to demo state transition functionality
- try `python -m nx3d diffusion`

Sat Sep 18 2022

- refactored and set up for DiGraph support
- lighting improvements
- debugged edge and node labels, colors
- renamed main class from NxPlot to Nx3D

Sat Sep 17 2022

- revved version to propagate README fix, essentially a no-op