Allow url.format to take the 'path' parameter

I know there are already a few tickets relating to the url parse/format inconsistency (https://github.com/joyent/node/issues/3770), but I'm wondering if adding support for 'path', (pathname + search) makes sense. I don't believe this will create any stability issues, as 'path' is not a part of currently allowed url.fromat parameters. What do you think?