Added kit4_area_4 to regions.py. Added plot_speed_difference_relative.py plots relative difference. Notebook to plot drag at locations due to kelp (kelp_drag_speed_diff). check_usage_full.py properly parses the output of qstat -xf to get the core hours used by each user. ncgrid2mat.py saves a few different files now basic grid, basic grid + DA currents, basic grid + DA currents+ interped currents. Other minor changes.