Added a background music component to MIDISoundTranslator
It's currently only producing one mood (slightly spooky)
Merge branch 'master' of https://github.com/jonhare/WAISFest13.git

Conflicts:
	FlickrVisualisations/src/main/java/uk/ac/soton/ecs/wais/fest13/sound/midi/MIDISoundTranslator.java
Fixed it so that the note music isn't playing if there are no social
comments.
Set initial background music mood to something less obtrusive.
moved BackgroundMusic to its own class - it was getting big
Updates MidiSoundTranslator to update mood of both the background music
and the comment-notes.
Merge branch 'master' of https://github.com/jonhare/WAISFest13

Conflicts:
	FlickrVisualisations/src/main/java/uk/ac/soton/ecs/wais/fest13/sound/midi/MIDISoundTranslator.java