Use "window" instead of "top" for AudioContext

Author: jdnichollsc

zzfx.js

@@ -14,4 +14,4 @@ zzfxV=.3
 zzfxR=44100
 
 // zzfxX - the common audio context
-zzfxX=new(top.AudioContext||webkitAudioContext);
+zzfxX=new(window.AudioContext||webkitAudioContext);