session: Remove volume_normalization setter/getter
session: Remove volume_normalization setter/getter

felix1m/pyspotify,felix1m/pyspotify,mopidy/pyspotify,kotamat/pyspotify,kotamat/pyspotify,kotamat/pyspotify,jodal/pyspotify,mopidy/pyspotify,felix1m/pyspotify,jodal/pyspotify,jodal/pyspotify