Add support for noproxy list

[tbhi]

It would be good if there was a noproxy list like curl supports:

--noproxy <no-proxy-list>
          Comma-separated  list  of hosts which do not use a proxy, if one
          is specified.  The only wildcard is a single * character,  which
          matches all hosts, and effectively disables the proxy. Each name
          in this list is matched as either a domain  which  contains  the
          hostname,  or  the hostname itself. For example, local.com would
          match  local.com,  local.com:80,  and  www.local.com,  but   not
          www.notlocal.com.  (Added in 7.19.4).

[troglobit]

Have no need for this myself at the moment. But patches are always welcome! :)

[troglobit]

If we ever add optional libcurl support, I guess this feature would be a no-brainer?