[Discuss-gnuradio] UDP source/sinks (revised)

[Tom Rondeau]

Alright, the new code for the UDP source/sinks was just checked in with all
the fixes and additions required to actually make it, well, work.

I tested it out in my lab using the new audio_source.py and audio_sink.py
example scripts (in python/hier/networking) to stream my latest podcast of
Fresh Air across at 48 ksps. Granted, this was on my local GigE switch, but
it came through flawlessly.

I don't know how well it will really be able to perform over the net. On the
other hand, these blocks are really meant more for testing and
proof-of-concept (like my guys in our lab can use it when they don't have
access to our USRPs just to get the code working).

I've also now added the ability to set the source and destination addresses
by their hostname or the IP address instead of just the IP address.

Hope it helps.
Tom