=htc,htp #16099 remove all special treatment for ISO-8859-1, switch to UTF-8 as default charset everywhere
!str #16102 Fold Tap/Drain into Source/Sink

* Fold Tap/Drain into Source/Sink
* Create Source/Sink helpers to create all Sources/Sinks
* Make concrete Source/Sink implementations private[scaladsl2]
Merge pull request #16092 from akka/wip-remove-tap-and-drain-from-view-ban

!str #16102 Fold Tap/Drain into Sink/Source
Merge pull request #16100 from spray/wip-16099-mathias

=htc,htp #16099 remove all special treatment for ISO-8859-1, switch to U...
+htp #15924 import FutureDirectives from spray
Merge pull request #16091 from spray/w/15924-future-directives

+htp #15924 import FutureDirectives from spray
=htc smaller improvements in FastFuture
=htp add support infrastructure for folding over tuples with a binary poly-function
=htp refactor tuple join to foldLeft-based implementation, unify tuple operations
!htp #16101 improve basic directive infrastructure, add more scaladoc, fix smaller problems
=htp enable tests that were erroneously disabled due to specs2 -> scalatest copy-pasta
=htp small improvement to Marshaller
!htp #15935 clean up and extend unmarshalling infrastructure
+htp #15929 port ParameterDirectives from spray