Mob Spawners and Music Block Polishing

I've been mainly working on the mob spawner tonight.  It can now spawn everything that is an entity besides items (though will add that later). Should be interesting to see what people will do with the new entities.  Also polishing up the music block interface so more music is visible and you can set the fade in and fade out duration.

Now for a video demoing off a new feature of the mob spawner.