Firefox Web Audio fixes.
Firefox Web Audio fixes.

Fixes #145.

Disar/flambe,mikedotalmond/flambe,Disar/flambe,markknol/flambe,playedonline/flambe,markknol/flambe,playedonline/flambe,weilitao/flambe,Disar/flambe,aduros/flambe,playedonline/flambe,weilitao/flambe,Disar/flambe,aduros/flambe,markknol/flambe,aduros/flambe,mikedotalmond/flambe,mikedotalmond/flambe,weilitao/flambe,playedonline/flambe,weilitao/flambe,aduros/flambe,mikedotalmond/flambe