Makes the tempo (speed of a piece of music) faster or slower by the amount you say.
This function only works on the Calliope mini and in some browsers.
music.changeTempoBy(20)bpm is a number that says how much to
change the bpm (beats per minute, or number of beats in a minute of
the music that the Calliope mini is playing).This program makes the music faster by 12 bpm.
music.changeTempoBy(12)This program makes the music slower by 12 bpm.
music.changeTempoBy(-12)