[ADD] Barro

Change:

Track 15 -> [DLC] Track 15

Track 16 -> [DLC] Track 16

Add:

[DLC] Track 20

[DLC] Track 21

[DLC] Track 22

[DLC] Track 23

We can't mark charts as DLC, only groups. Should we make another group for Track #15 to Track#23 ? 

After playing the game, I created a new group with the tracks.

Done. 😄