1. Generate a correct Content-Length header visible through the info() method
if a request to open an FTP URL gets a length in the response to RETR.
2. Take a third argument to urlretrieve() that makes it possible to progress-
meter an urlretrieve call (this is what I needed the above change for).
See the second patch band below for details.
3. To avoid spurious errors, I commented out the gopher test. The target
document no longer exists.