Implement basic map visualizer in Treemower

[yoos]

Currently, Treemower just prints out a list of coordinates that comprise the best path. It would be nice to visualize this as a graph of some sort overlaid on the infomap or something.

[yoos]

Modified Yawei's plotter to animate path: https://github.com/osurdml/treemower/blob/enhancement/18_visualizer/Matlab-Version/animplot.m

First problem with this is that the path is drawn backwards because the data itself is exported backwards. Working on this.

Second problem is that I'd like to see more the scores changing live (with a useful colormap) as well as the lookahead steps. The plot as-is is better than nothing, but debugging with this is going to be hard.

Current thought is to pipe text either straight to gnuplot or a Python script, so something like this:

./treemower data/costmap.txt | ./treevis.py

[yoos]

[yoos]

Done: https://github.com/osurdml/treemower/commit/f3479aaec1e104613b7b35b6cd46676691f43321