Bump ending copyright year to 2017
Bump ending copyright year to 2017

ZizhengTai/http4s,reactormonk/http4s,rossabaker/http4s,ZizhengTai/http4s,ChristopherDavenport/http4s,rossabaker/http4s,ChristopherDavenport/http4s,ChristopherDavenport/http4s,aeons/http4s,reactormonk/http4s,ZizhengTai/http4s,aeons/http4s,aeons/http4s,http4s/http4s,reactormonk/http4s