http4s/http4s — pull request #50 by bryce-anderson (2014-08-13 16:11:32+00:00)
Title: Improve Headers functionality

* Efficiently concat collections, removing dupilicate headers that are not `Recurring`
* Fix problem with Status EntityBuilders that would duplicate the headers associated with the Writable

As a bonus, this gives a 6% performance boost to blaze and I assume servlet backends as well.