Implement a recent shortest paths algorithm

[pnevyk]

source

I haven't studied the paper yet, but I would like to have this included in the library. The reasons are:

• There would be an implementation of an algorithm for shortest paths with negative weights faster than Bellman-Ford (there have been other algorithms, but this was is claiming the best time complexity bound.
• The abstract claims that the algorithm is "simple". Whereas it is definitely more complex than Bellman-Ford, it should be simpler than recent alternatives.
• Implementing the algorithm will show if our API and infrastructure is sufficient for a modern algorithm, or show gaps that we need to fill.

[pnevyk]

There is another paper that discusses an SSSP algorithm with lower time complexity that standard algorithms. Apart from the algorithm itself, it refers to some recent state-of-the-art papers for different variants of the problem.