introduce Url.netloc (see #217)
remove superfluous code
Merge pull request #218 from t-8ch/url_netloc

Url netloc
Added units to the doc for timeout

timeout is specified in seconds, but in the doc, it was unclear.
Merge pull request #219 from nipunn1313/master

Added units to the doc for timeout
Correctly set Host header when using a proxy

Fixed a bug in _set_proxy_headers that ignores the port when setting the
'Host' HTTP header while a proxy is used.