phly/http — pull request #5 by weierophinney (2014-10-01 15:43:04+00:00)
Title: Multiple headers in Server

Not every header can be concatenated with a comma. `Set-Cookie` is an example.

So this looks wrong:

https://github.com/phly/http/blob/master/src/Server.php#L188

You'll want to loop through the header values and set `header()`s `$replace` argument to false.