Redo Shortest Path with LightGraphs

[jlperla]

• Can add it to the more rich set of packages, should have easy ways to traverse, etc.
• Has gplot
• Could load the graph from a file, or just display a simple one inline rather than the fancy one.
• Can use the fixedpoint

[jlperla]

Should then point people to https://juliagraphs.github.io/LightGraphs.jl/latest/pathing.html#General-properties-of-shortest-path-algorithms-1 as an example of "Look for Better algorithms in other packages!"