by Alessandro Buccato
v1.5 - old edition: see v1.7 firefox edition
v1.2: add chrome option setup
v1.3: fix YouTube default rotation
v1.4: edit headset setup
v1.5: add toast show
start Spotify and control audio volume, when headset is plugged and any application is open.
however, if chrome is open and then headset is plugged, enable orientation sensor. when headset is unplugged, Spotify or chrome are closed, audio volume and orientation screen is restored.