Parallel Dijkstra

The initial version has only parallelized the outer loop of the algorithm and has not been done in the most efficient way however has provided a significant speed up for the larger graph sizes.

For each graph the source node was the top left and the goal node was the bottom right, both the parallel and sequential implementations found the same path

map	Sequential Dijkstra (ms)	Parallel Dijkstra (ms)
32x32	1	8.49
64x64	3.8	16.73
128x128	16.2	33.20
256x256	68.01	66.38
512x512	277.07	142.77
1024x1024	1146.38	405.50
2048x2048	4954.72	1763.95