** Revision based on feedback

* API

define_hook("proxy_enabled_hook");
define_hook("proxy_disabled_hook");
define_hook("proxy_profile_updated_hook");

// Proxy modes.
PROXY_NONE        = 0;
PROXY_AUTO_DETECT = 1;
PROXY_AUTO_CONFIG = 2;
PROXY_SYSTEM      = 4;
PROXY_MANUAL      = 5;

define_keywords("$http", "$ssl", "$ftp", "$gopher", "$socks", "$socks_ver",
                "$socks_dns", "$excludes" "$ac_url", "$ac_retry_min",
                "$ac_retry_max", "$ac_timeout", "$mode");
function proxy_define_profile(name) {}

function proxy_remove_profile(name) {}

function proxy_enable(name) {}

function proxy_disable() {}

function proxy_toggle() {}
interactive("proxy-toggle", "Toggle use of proxy.", proxy_toggle);

function proxy_enable_mode_line(formatter) {}


* Changes

Eliminate 'proxy_update_profile' - 'proxy_define_profile' will handle updating existing profiles.

The proxy mode is now part of the profile.

retroj suggests having some pre-defined profiles for system and auto-detection. Profiles for popular
proxies like privoxy might not be a bad idea either.

Note that one would switch from one profile to another by calling 'proxy_profile_enable' with the new
profile name, without the need to first call 'proxy_disable'.