[PD] receive UDP message from 224.0.0.1

[João Pais]

> Sorry to break in, but I may be setting up some Windows Pd instances using OSC in the near future; is this something that will need to be dealt with even when not using multicast?

this problem doesn't happen when not using multicast - which I never 
heard of before this week - but have been using OSC for many years with 
no issues.

But it's confirmed, the problem is with the windows driver (or the 
system, firewall is open or even off for testing). Using ubuntu in both 
laptops I can multicast either to 224.0.0.1 or to the IPs in the help patch.