Added a place marker to allow volume change during app. Right now it's either loud or off. There isn't a way to allow the volume to gradually go up and odwn based on the values set in settings.
modified pc and android impls to ensure new calls are made. These still have the same effective outcome (kill and start) until the equivalent is coded on these platforms to pause and resume the music.
fixed bug with iOS sound effects not playing. Forgot to assign the key to the associated music sample
