Add --proxy-type functionality for Chrome/Chromium renderers.

[zonicdoe]

Proposed change

Add some code that allows you to specify the type of proxy to use with the Chrome/Chromium renderer.

Fixes

It prevents the error shown below when using a socks proxy with the Chrome/Chromium renderer:

[maaaaz]

Hello @zonicdoe,

Thanks, you're right.
It might be a lack of documentation but you can already specify the proxy type in the --proxy option for chrome/chromium renderers.

A --proxy socks://foobar or --proxy http://foobar should already work without the need of --proxy-type option which was used in the early days as a direct mapping of phantomjs options.

[zonicdoe]

Now that you mention it, it seems pretty obvious. Thanks ;)