[DNM] - Area-based Jukebox

A jukebox which alters the ambient sound in the current area and plays it with 100% probability.
Leaving the area stops the ambient sound.
Entering the area resumes playing the ambient sound, assuming you walked there yourself (for now).

![Feel it!](https://www.dropbox.com/s/mjxugr4z77t7452/JukeIt.png?dl=1)
Working fine when building a fork of your branch : all three ```world``` output working fine...
Maybe a clean rebuild would solve the problem ?