Proxy Authentication

[brlogan]

There is interest in having proxy authentication support. It should be fairly simple to add support for basic auth using something along the lines of:

proxy_auth_handler = urllib.request.HTTPBasicAuthHandler()
proxy_auth_handler.add_password('realm', 'host', 'username', 'password')
handler_list.append(proxy_auth_handler)

[akmalhisyam]

bump

[gtback]

I would gladly accept a pull request for this feature, but I don't personally have a great way to test it.
I'd also love to switch all of libtaxii to use requests rather than urllib, but haven't had the time to do it.