Merge: Audio management for android + audio Abstraction API

Fixes some problems with the audio management for the android platform. The audio API for android still needs some work but is fine to use now !
The Abstraction API for sound management is very simple for now

Pull-Request: #1101
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>
Reviewed-by: Jean Privat <jean@pryen.org>
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>