With the exception of use in three quotes as well as our inlcuded copy
of the GPL, all use of the Free Software Foundation's postal address
has been removed.
Re #320.
Scanners are currently passed around by name, which is actually a URL.
Each function parses the URL a little bit, depending on what it needs,
and then sets the same curl options.
This refactors parsing out into a single escl_parse_name() function
called from sane_open and then passes around the resulting ESCL_Device
instead of the raw name. To set up the curl handle, the new
escl_curl_url() reconstructs a URL from the parsed ESCL_Device and sets
the appropriate options on the handle. Each place that makes a curl
call is updated to use the new function.