Pass in custom path to input_csvs

[tylerlum]

Right now, we pass in -g csv like

./build/bin/pathfinder_cli -p 10 --navigate 49.275 236.838 49.318 236.685 -g csv --save

Which reads csvs from the hardcoded path input_csvs. However, we should not pass in a hardcoded text csv, but give it a path eg.

./build/bin/pathfinder_cli -p 10 --navigate 49.275 236.838 49.318 236.685 -g test_cases/high_wind --save

Where the root directory will have a folder test_cases/high_wind that has

angles2d-0.csv  angles2d-1.csv  angles2d-2.csv  angles2d-3.csv  lats2d.csv  lons2d.csv  magnitudes2d-0.csv  magnitudes2d-1.csv  magnitudes2d-2.csv  magnitudes2d-3.csv

[tylerlum]

Resolved in #59