[twill] Downloading a binary file

[Jamal Mazrui]

I want to develop a web crawler with twill.  What might be the best way
to download non-HTML files while retaining state?  For example, a script
might log into a site and then search for particular .mp3 files there.
I want cookies and the Referer header to be handled correctly when
making a download request.  I have found twill examples that save
text/HTML but not binary files.

Jamal