get num/denom (rational-n x) (rational-d x)
added srcaddr option to OSC

setting (io:osc:netaddress? #t)
will now pass an ip address "192.168.1.1" and a port 7777 as the first
two args to io:osc:receive

So for example:

(define my-osc-receive
  (lambda (timestamp address srcip srcport . args)
    (println 'msg 'from 'ip srcip)))