Tidying up source code for release. Also refactored World to use a Group instance, rather tha duplicate functions.

examples/sound1.php

@@ -30,6 +30,7 @@
 	function create() {
 
 		game.stage.backgroundColor = '#182d3b';
+		game.input.touch.preventDefault = false;
 
         music = game.add.audio('boden');
         music.play();