Following https://github.com/Yonaba/Jumper/blob/master/jumper/search/jps.lua
If we're checking a node that is in the closed list, is it possible we might have a shorter path that we need to change its G and F score? Otherwise, if it's not shorter, do we stop at the closed node and expand in other directions?
Do we mark all the nodes we check while expanding as visited/closed?
Why does the jump function only return 1 forced neighbour? Couldn't there be more than one?
