Provides interfaces and classes for calculating (geodesic) distances and shortest paths. Currently includes:

- `DijkstraDistance`: finds the distances from a specified source vertex to other vertices in a weighted graph with no negative cycles
- `DijkstraShortestPath`: extends `DijkstraDistance`, also finds shortest paths
- `Distance`: an interface for defining vertex-vertex distances
- `PrimMinimumSpanningTree`: identifies the spanning tree for a graph of least total edge weight
- `ShortestPath`: an interface for shortest-path algorithms
- `ShortestPathUtils`: utility functions for manipulating shortest paths
- `UnweightedShortestPath`: finds the distances from a specified source vertex to other vertices in an unweighted graph