bpo-29613: Added support for SameSite cookies (GH-6413)

* bpo-29613: Added support for SameSite cookies

Implemented as per draft
https://tools.ietf.org/html/draft-west-first-party-cookies-07

* Documented SameSite

And suggestions by members.

* Missing space :(

* Updated News and contributors

* Added version changed details.

* Fix in documentation

* fix in documentation

* Clubbed test cases for same attribute into single.

* Updates

* Style nits + expand tests

* review feedback
diff --git a/Misc/ACKS b/Misc/ACKS
index b951446..8b2931f 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1461,6 +1461,7 @@
 Daniel Shaulov
 Vlad Shcherbina
 Justin Sheehy
+Akash Shende
 Charlie Shepherd
 Bruce Sherwood
 Alexander Shigin
diff --git a/Misc/NEWS.d/next/Library/2018-04-07-13-49-39.bpo-29613.r6FDnB.rst b/Misc/NEWS.d/next/Library/2018-04-07-13-49-39.bpo-29613.r6FDnB.rst
new file mode 100644
index 0000000..a679cd9
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-04-07-13-49-39.bpo-29613.r6FDnB.rst
@@ -0,0 +1,2 @@
+Added support for the ``SameSite`` cookie flag to the ``http.cookies``
+module.