Add memory to bus icon route color to handle temporary null routes

[bryantran24]

When the API briefly returns an null route, bus icons immediately reset to the default color, causing confusion. Add short-term memory to bus icon colors so they retain the last known route color for a short time before reverting to default.

Also currently the locations api doesn't return the route_name it is https://api-shuttles.rpi.edu/api/velocities that does. So connect that to the buses so we actually get the correct bus color.