* Document why set_result() calls are safe
* Cleanup gather(). Use public methods instead of hacks to consume the
  exception of a future.
* sock_connect(): pass directly the fd to _sock_connect_done instead of the
  socket.

Patch by A.M. Kuchling.

- clarified the distinction between text encodings and other codecs
- clarified relationship with builtin open and the io module
- consolidated documentation of error handlers into one section
- clarified type constraints of some behaviours
- added tests for some of the new statements in the docs

availability of the function is checked during the compilation. Patch written
by Bernard Spil.

ssl.PROTOCOL_SSLv23 protocol by default, not ssl.PROTOCOL_SSLv3, for maximum
compatibility and support platforms where ssl.PROTOCOL_SSLv3 support is
disabled.

the waiter future before setting its result.

10.4 systems do not allow creation of files with such filenames.

Patch by Vajrasky Kok.

Patch by Dmitry Kazakov.

Reported by Damien Marié.

asyncio.BaseEventLoop now use the identifier of the current thread to ensure
that they are called from the thread running the event loop.

Before, the get_event_loop() method was used to check the thread, and no
exception was raised when the thread had no event loop. Now the methods always
raise an exception in debug mode when called from the wrong thread. It should
help to notice misusage of the API.

* Fix pyflakes warnings: remove unused imports and variables
* asyncio.test_support now uses test.support and test.script_helper if available

instead of reading /dev/urandom, to get pseudo-random bytes.