do_fetch() - which retrieves one file calling fetch_url() or fetch_ftp()
as necessary.
* don't http redirect more than 5 times for a given url
* send `User-Agent: NetBSD-ftp/1.4' header in http requests. (suggested
by Christoph Badura <bad@ora.de>)
* cleanup http return code parser, and add support for:
- 300 `Multiple Choices' - but only if the server returns a
preferred url in a Location: header because i'm *not* adding
a html parser to provide the user with options.
- 305 `Use Proxy [given in Location: header]'. (XXX: not tested)
* support http redirects to non-proxied ftp://urls. (bug discovered by
Chris Demetriou <cgd@netbsd.org>)
* auto-login to an ftp site (using the FTP protocol) if an ftp://host/dir/
style url is given and ftp_proxy is set. whilst this is less orthoganol
with other ftp://host/file urls it's *much* more convenient.