Add support for proxy configuration

[keithmoss]

http = httplib2.Http(proxy_info = httplib2.ProxyInfo(httplib2.socks.PROXY_TYPE_HTTP_NO_TUNNEL, 'proxy.dli.wa.gov.au', 8080, proxy_user = '', proxy_pass = '') )

Affected:

• run_oauth2()
• discovery_build()
• Anything else that instantiates an httplib2 object.

Provide config via...a JSON config file? Command-line params?

[keithamoss]

http://macinedu.wordpress.com/2014/01/30/python-proxies-and-mac-os-x-oh-my/ might do the trick