Fixed a bug in the MediaQueue where the active song did not default to -1.
This would cause existing games to think that a song was available already
when it wasn't. The XNA default is -1.
Merge remote-tracking branch 'upstream/develop' into develop
Merge pull request #1690 from dellis1972/develop

Fixed default values for MediaQueue ActiveSongIndex. I saw this when I was doing the Song.loadFromUri implementations too. Good eye Dean!