Function game::edit::traffic_signals::gmns::import

pub fn import(
    map: &Map, 
    i: IntersectionID, 
    path: &str
) -> Result<ControlTrafficSignal>

This imports timing.csv from https://github.com/asu-trans-ai-lab/Vol2Timing. It operates in a best-effort / permissive mode, skipping over mismatched movements and other problems and should still be considered experimental.