EMI: Move sound-related warnings to a separate Debug-channel.

This moves a lot of the noise created from the music-system's various warnings into a separate debug-channel, this helps greatly for i.e. the massive querying that is done during the intro.

However, some of these warnings might be stuff people WANT to be warned about in general (i.e. "TODO: Implement this-style warnings). So, any comments on what keep, and what to move, is greatly appreciated.