!htc Replace `Deferrable` with `FastFuture`
!htp,htk Upgrade from `Deferrable` to new `FastFuture`, closes #15962
!htc Remove obsolete ProtectedHeaderCreation construct
!htc Tighten up header model some more, update spec links
=htc Improve handling of `Transfer-Encoding` header, closes #15490
Merge pull request #15969 from spray/wip-15490-mathias

Improve handling of `Transfer-Encoding` header
Merge pull request #15975 from spray/wip-15962-mathias

 Remove `Deferrable[T]` and replace with POF (plain old Future)
+hco #15945 Make Tcp and Http server binding closeable
Merge pull request #15983 from akka/wip-15945-unbind-tcp-and-http-connection-ban

+hco #15945 Make Tcp and Http server binding closeable
!str,hco #15945 Make creation of ServerBinding public again
Merge pull request #15986 from akka/wip-15945-clean-up-unbind-ban

!str,hco #15945 Make creation of ServerBinding public again
Merge remote-tracking branch 'origin/release-2.3-dev' into w/15910-encoding-infrastructure

Conflicts:
	akka-http-core/src/main/scala/akka/http/model/HttpEntity.scala
fix string descriptions in HttpEntity.transformDataBytes implementations