Fix music not being looped sometimes
Prevent channel less than 0 from being passed
Set up a new music display element with an attached music name, it displays a scrolling text of the currently playing music
Fix music packet processing issues
Make SFX slider responsible for all music channels besides 0 (actual music)
scrolltext.cpp code recipe was taken from https://stackoverflow.com/questions/10651514/text-scrolling-marquee-in-qlabel - thanks to leemes for that one, I only adapted it for newer C++ version and tweaked some stuff.
