3 - custom maximum download time
4 - custom least download speed acceptable
6 - guesses protocol from host name unless specified
8 - progress bar/time specs while downloading
9 - PROXY environment variables support
24 - custom headers (that can replace internally generated headers)
25 - custom user-agent string
26 - custom referer string
28 - proxy authentication
33 - (all the HTTP features)
41 - single file size information (compare to HTTP HEAD)
44 - dir listing names-only
47 - upload via http-proxy as HTTP PUT
51 - simple "range" support
55 - connection negotiation
59 - full LDAP URL support
62 - extended DICT URL support
72 *2 = requires OpenLDAP