Possibility to change proxy runtime

[pdeszynski]

Added setProxy method for to a page:

page.setProxy('http://my.proxy.com:8080');
 //or
page.setProxy('socks5://someproxy:8080');

Theoretically username and password should work also:

http://username:password@example.com/

There's also a possibility to set proxy using page.openUrl method:

page.openUrl('http://example.com', 'get', {'proxy': 'http://my.proxy.com:8080'});

[vitallium]

LGTM
/cc @ariya

[zackw]

Merged, thank you.

Would you consider writing some documentation for this new feature? It goes in gh-pages.

[a0s]

Have any idea how to call setProxy when --webdriver is using (Watir::Browser context)?
For example

browser.driver.execute_script("return page.setProxy('socks5://localhost:5555');")

is not working