Add new fn rt for bypassing any bpm scaling:
Add new fn rt for bypassing any bpm scaling:

+use_bpm 120  # modifies all time to be half
+play 50
+sleep 1      # actually sleeps for half of a second
+play 62
+sleep rt(1)  # bypasses bpm scaling and sleeps for a second
+play 72

jweather/sonic-pi,jweather/sonic-pi,jweather/sonic-pi,jweather/sonic-pi,jweather/sonic-pi