gh-140 HttpClientRequest.continueHandler should take a function
gh-140 Leave only one putHeader() method, which takes a vararg
gh-72 HttpClientResponse.cookie() should return a Scala list
Kicked unnecessary assertion in ignoreReply test.
This assertion might bite us, if the system is under heavy load, or similar.

Signed-off-by: Joern Bernhardt <jb@campudus.com>