#107: Set x-forwarded-for header (amongst others)

[jfhbrook]

These commits should fix the bug where the x-forwarded family of http headers are not being added to proxied requests.

[indexzero]

This looks good, but shouldn't:

  req.headers['x-forwarded-for']   = req.connection.remoteAddress || req.connection.socket.remoteAddress;

be

  req.headers['x-forwarded-for']   = req.connection.remoteAddress || req.socket.remoteAddress;

[jfhbrook]

Yes. I thought I fixed that. >_<

edit: Fixed it.