Boombox easter egg reworked.

[Damgam]

• Boombox is no more, the unit and the spawner have been completely removed. Unit being around the place with a lot of exceptions set up, was causing problems, especially when there was combat happening around it.
• The music easter egg is now instead triggered by quickly skipping 3-4 tracks (depending if you do the first skip early in the track or not, since that also counts as skip)
• The track will now play in menu only if you encountered the easter egg AND you did not skip it after 60 seconds.