change bounding box colors to be colorblind-friendly

[andyroo]

Just saw in another post that some colorblind folks can't tell the difference between the ground and non-ground sides of the bounding box. It would be pretty easy to change the colors to be colorblind-friendly. One thought was black ground sides and white other sides, but if you changed the hue of the red to be dark red and kept the gray edges light gray (or lightened them) that would probably be enough.