Adding Edge Weighted Algorithms

[RaiyanC]

No description provided.

[mtorpey]

I've rebased this as a single commit and force-pushed to Raiyan's branch. Raiyan, if you want your original commit history it's at https://github.com/mtorpey/Digraphs/tree/edge-weight-algorithms-raiyan-original

Hopefully we can get this merged at some point!

[mtorpey]

There's a lot of good stuff in here, but I added a couple of TODOs and there's a little work to be done (probably by me) before it's good to merge. But I'm confident this will broadly make it!

[mtorpey]

I'm going to try to merge this one bit at a time, to keep things manageable.

Approximate todo list:

• EdgeWeightedDigraphMinimumSpanningTree: Edge-weights #3: minimum spanning trees #650
• DigraphEdgeWeightedShortestPath[s]: Edge weights #4: shortest path(s) #656
• DigraphMaximumFlow/DigraphMinimumCuts
• RandomUniqueEdgeWeightedDigraph
• DigraphFromPath[s]
• DotColoredEdgeWeightedDigraph

[mtorpey]

The latest version of this that I've got is at https://github.com/mtorpey/Digraphs/tree/edge-weight-algorithms

As mentioned above, I'm making this into PRs one bit at a time.