Fix issue 829 -- error message is displaying wrong incorrect result.
Merge pull request #831 from erkyrath/master

Fixed incorrect error message in _when_complete (#829)
Update twisted test blacklist for the newly-released 13.1.0.
Add apostrophes to xhtml_escape.

Closes #833.
Close pipe file descriptors if subprocess.Popen fails.

Closes #834.
Clear local variables in IOLoop to allow GC before we start polling.

Closes #836.
Use TracebackFuture for all internal Futures for better tracebacks on py2.x.
Update FacebookGraphMixin with new authorization url.

The old url still works, but results in an extra redirect.
Clear the loop variable in addition to the callback list.

Closes #844.
Start next release notes
Unify lists of errnos used in IOStream.

We generally want to treat aborted connections the same regardless of the
specific errno, but some calls caught ECONNRESET and ECONNABORTED
while others only caught ECONNRESET.  Reported in #828.
Clear the write buffer when an IOStream is closed.

Closes #828.
Fixed laziness of current_user in UI modules, and added tests for current_user. #820
Fix exception in StaticFileHandler when range requested is larger than file.
Correctly handle EAGAIN when writing to PipeIOStreams

BaseIOStream._handle_write needs to catch IOError and OSError as
well as socket.error in order to handle EAGAIN when writing to a
PipeIOStream (which doesn't appear to raise socket.error when the
buffer is full).

This also provides consistency with the exceptions caught by
BaseIOStream._read_to_buffer.
Merge pull request #848 from SuprDewd/issue_820

Fixed laziness of current_user in UI modules, and added tests for current_user.
Merge pull request #851 from taguchimail/master

Correctly handle EAGAIN when writing to PipeIOStreams
Crude fix for issue #855: automatically initiate SSL handshake in SSLIOStream.
Perhaps this should be exposed as an option instead?
Add in Google OAuth2 support.
Fix up documentation for the class and the Sphinx reference.