+pro create akka-http-parent project as an anchor to run aggregate tasks on
=htc #16488 add missing assertions in tests

 - replaced pure `===` by `shouldEqual`
 - fixed the backport of spray/spray#927 in ae8c47acc170907ee9c8dfbcb946b400035f6877
 - fixed HttpHeaderParserSpec
+doc apply new docs design to akka-docs-dev
Merge pull request #16457 from spray/w/introduce-http-aggregate-project

+pro create akka-http-parent project as an anchor to run aggregate tasks on
Merge pull request #16551 from ktoso/docs-dev-styling

+doc apply new docs design to akka-docs-dev
!str #16455 Remove unused fanout settings
Merge pull request #16489 from spray/w/16488-fix-http-tests

=htc #16488 add missing assertions in tests
!str #16557 Rename Source.singleton to Source.single
=str #16479 Make constructor of FreeDirective internal
+doc quickstart docs for akka streams, initial version
Merge pull request #16526 from ktoso/docs-streams-quickstart-ktoso

akka-streams docs - quickstart
Merge pull request #16558 from akka/wip-16479-FreeDirective-patriknw

=str #16479 Make constructor of FreeDirective internal
Merge pull request #16556 from akka/wip-16455-cleanup-materializer-settings-patriknw

!str #16455 Remove unused fanout settings
Merge pull request #16559 from akka/wip-16557-Source.single-patriknw

!str #16557 Rename Source.singleton to Source.single
+doc akka streams docs, flowGraphs
Merge pull request #16555 from ktoso/docs-streams-graphs

akka streams docs: graphs
move documentation around a bit and setup high-level documentation structure
a first set of documentation imported and adapted from spray ones