Play sound when voice triggered
Play sound when voice triggered

During development, it is still slightly surprising that voice
detection actually works, so it is nice to have some audible feedback
trigger detection worked when my eyes are not on the console.

Signed-off-by: Mike Erdahl <4d54a305c7882f4f7bf4f516c8c96232922edadd@gmail.com>

merdahl/AlexaBeagleBone2