Nicer Units

[samuel-skean]

We use km/h and mph. Pick one, ideally. But both mi/h and kph sound kinda wrong!

[samuel-skean]

I kinda like it now?

[samuel-skean]

But units should be made distinct with different colors, or something.
And maybe it'd be worth the extra complexity to let people configure exactly which units they want to support. If they want more than two units, we show a drop-down!