Simple A* pathfinding algorithm
Set the edges and straight line distances between cities (heuristic) via the cidades.csv file
First column: 'e' for edge or 'h' for heuristic,
Second column: first city
Third column: second city
Fourth column: value
To initialize the algorithm, set one row like: a*, from city, to city
Based on this (great!) tutorial, by @Nicholas-Swift (thanks, Nicholas): https://medium.com/@nicholas.w.swift/easy-a-star-pathfinding-7e6689c7f7b2