Add http_proxy and https_proxy support to web/client.py

[fsteinel]

for unix: http_proxy=os.environhttp_proxy? https_proxy=os.environhttps_proxy?

[fsteinel]

see also Issue #1895

[fsteinel]

and Issue #463 with Issue #885

[itamarst]

Personally I'd be happier if more work went into finishing web2, rather than improving web.

[exarkun]

Plenty of people are using web right now. Ignoring their use-cases because maybe someday web2 will be usable strikes me as a bad idea.

[ghazel]

and #1774

[exarkun]

If someone really wants to add this to getPage (as I suspect the original reporter had intended), that's fine. However, I think it would be much more productive to add this as an Agent-alike instead.

[exarkun]

Duplicate of #1774, actually.