Added a flag for end station for direction

[emresaglam]

Hi Eric,

I wanted to highlight the direction of the train in the real time departures section and added a flag to do that (-d).

Now when you do: bart -d millb est embr It highlights the Millbrae direction for the Embarcadero station.

If you find it useful (And it works for you) feel free to merge it ;)

Cheers Emre