asyncio: Fix formatting of the "Future exception was never retrieved" in
release mode

--HG--
branch : 3.4
asyncio, test_events: Ignore the "SSL handshake failed" log in debug mode

--HG--
branch : 3.4
asyncio: Coroutine objects are now rejected with a TypeError by the following
functions:

* add_signal_handler()
* call_at()
* call_later()
* call_soon()
* call_soon_threadsafe()
* run_in_executor()

Fix also the error message of add_signal_handler() (fix the name of the
function).

--HG--
branch : 3.4
asyncio: BaseSelectorEventLoop.close() now closes the self-pipe before calling
the parent close() method. If the event loop is already closed, the self-pipe
is not unregistered from the selector.

--HG--
branch : 3.4