Start accumulating release notes

website/sphinx/releases.rst

@@ -4,6 +4,7 @@ Release notes
 .. toctree::
    :maxdepth: 2
 
+   releases/next
    releases/v2.1.1
    releases/v2.1.0
    releases/v2.0.0

website/sphinx/releases/next.rst

@@ -0,0 +1,34 @@
+What's new in the next release of Tornado
+=========================================
+
+In progress
+-----------
+
+``tornado.template``
+~~~~~~~~~~~~~~~~~~~~
+
+* Exceptions in template code will now show better stack traces that
+  reference lines from the original template file.
+* ``{#`` and ``#}`` can now be used for comments (and unlike the old
+  ``{% comment %}`` directive, these can wrap other template directives).
+* Template directives may now span multiple lines.
+
+Other modules
+~~~~~~~~~~~~~
+
+* `tornado.iostream.IOStream.write` now works correctly when given an
+  empty string.
+* `tornado.simple_httpclient` no longer hangs on ``HEAD`` requests
+  and responses with no content.
+* `tornado.websocket` has been updated to support the latest protocol
+  (as finalized in RFC 6455).
+* `tornado.platform.twisted` compatibility has been improved.  However,
+  only Twisted version 11.0.0 is supported (and not 11.1.0).
+* `tornado.ioloop.PeriodicCallback` no longer triggers duplicate callbacks
+  when stopped and started repeatedly.
+* `tornado.web` now behaves better when given malformed ``Cookie`` headers
+* `tornado.testing.main` supports a new flag ``--exception_on_interrupt``,
+  which can be set to false to make ``Ctrl-C`` kill the process more
+  reliably (at the expense of stack traces when it does so).
+* `tornado.process.fork_processes` correctly reseeds the `random` module
+  even when `os.urandom` is not implemented.