Update asyncio from the Tulip project

Major changes:

- StreamReader.readexactly() now raises an IncompleteReadError if the
  end of stream is reached before we received enough bytes, instead of
  returning less bytes than requested.

- Unit tests use the main asyncio module instead of submodules like events

- _UnixWritePipeTransport now also supports character devices, as
  _UnixReadPipeTransport. Patch written by Jonathan Slenders.

- Export more symbols: BaseEventLoop, BaseProactorEventLoop,
  BaseSelectorEventLoop, Queue and Queue sublasses, Empty, Full

Lib/asyncio/__init__.py

@@ -18,13 +18,17 @@ if sys.platform == 'win32':
         import _overlapped  # Will also be exported.
 
 # This relies on each of the submodules having an __all__ variable.
-from .futures import *
+from .base_events import *
 from .events import *
+from .futures import *
 from .locks import *
-from .transports import *
+from .proactor_events import *
 from .protocols import *
+from .queues import *
+from .selector_events import *
 from .streams import *
 from .tasks import *
+from .transports import *
 
 if sys.platform == 'win32':  # pragma: no cover
     from .windows_events import *
@@ -32,10 +36,14 @@ else:
     from .unix_events import *  # pragma: no cover
 
 
-__all__ = (futures.__all__ +
+__all__ = (base_events.__all__ +
            events.__all__ +
+           futures.__all__ +
            locks.__all__ +
-           transports.__all__ +
+           proactor_events.__all__ +
            protocols.__all__ +
+           queues.__all__ +
+           selector_events.__all__ +
            streams.__all__ +
-           tasks.__all__)
+           tasks.__all__ +
+           transports.__all__)