actually care for the map music switch
don't hide the pause button after unpause
merge C&C and RA music player logic

mainly code cleanup, but with the following improvements:
- scroll to current song which fixes #3360 and overlapping label
- use Rules.InstalledMusic & Sound.MusicPlaying everywhere
- separated C&C install logic and log catched exceptions
- save the music settings on back/close
Merge pull request #3600 from Mailaender/music-player-fixes

Fixed various music player problems