I updated dkftpbench to actually work with Poller_sigio,
I think. (Had to juggle things around a bit. one-shot
notification methods like Linux's sigio are a lot
touchier than level-sensitive notification methods like poll().)

I also support slow data rates; the throttling code didn't
work below about 10kbytes/sec before.

Not sure how well the sigio stuff works yet. Oddly,
there are some problems using select at low data rates.
Clearly I have some issues to address, so this is kind of
an alpha release. Feedback welcome.

New code at
http://www.kegel.com/dkftpbench/dkftpbench-0.27.tar.gz

- Dan