Fix music changes between areas

[N00byKing]

Changes:

Missed a Bug in #869.
When changing Areas, this line checks if Music is halted before playing the next track. However, it was never being halted, just paused.

Changing haltdasmusik to actually halt MusicTrack fixes it, but given the comment placed I wonder if this is the right approach. Could also check if Music is paused at the original location.

Legal Stuff:

By submitting this pull request, I confirm that...

• My changes may be used in a future commercial release of VVVVVV
• I will be credited in a CONTRIBUTORS file and the "GitHub Friends"
  section of the credits for all of said releases, but will NOT be compensated
  for these changes

[InfoTeddy]

Yeah, so the comment is there because we rely on the music to simply pause so custom levels can resume it later with resumemusic and musicfadein.

It looks like halting here will destroy the music, so halting here won't work. Instead it's probably better to change halted to return being paused.

[N00byKing]

So turns out there isn't a way to check if a voice is playing or not. Added a var to check if its paused

[InfoTeddy]

Tested and it seems to work fine. Music area changes now work again and resumemusic/musicfadein work as intended.