Improve stability of the proactor event loop, especially operations on
overlapped objects:

* Tulip issue 195: Don't call UnregisterWait() twice if a _WaitHandleFuture is
  cancelled twice to fix a crash.
* IocpProactor.close(): cancel futures to cancel overlapped operations, instead
  of cancelling directly overlapped operations. Future objects may not call
  ov.cancel() if the future was cancelled or if the overlapped was already
  cancelled. The cancel() method of the future may also catch exceptions. Log
  also errors on cancellation.
* tests: rename "f" to "fut"
* Add a __repr__() method to IocpProactor
* Add a destructor to IocpProactor which closes it
* _OverlappedFuture.cancel() doesn't cancel the overlapped anymore if it is
  done: if it is already cancelled or completed. Log also an error if the
  cancellation failed.
* Add the address of the overlapped object in repr(_OverlappedFuture)
* _OverlappedFuture truncates the source traceback to hide the call to the
  parent constructor (useless in debug).

Improve stability of the proactor event loop, especially operations on
overlapped objects:

* Tulip issue 195: Don't call UnregisterWait() twice if a _WaitHandleFuture is
  cancelled twice to fix a crash.
* IocpProactor.close(): cancel futures to cancel overlapped operations, instead
  of cancelling directly overlapped operations. Future objects may not call
  ov.cancel() if the future was cancelled or if the overlapped was already
  cancelled. The cancel() method of the future may also catch exceptions. Log
  also errors on cancellation.
* tests: rename "f" to "fut"
* Add a __repr__() method to IocpProactor
* Add a destructor to IocpProactor which closes it
* _OverlappedFuture.cancel() doesn't cancel the overlapped anymore if it is
  done: if it is already cancelled or completed. Log also an error if the
  cancellation failed.
* Add the address of the overlapped object in repr(_OverlappedFuture)
* _OverlappedFuture truncates the source traceback to hide the call to the
  parent constructor (useless in debug).

assertIs().

("enable-meta-key", "off") does crash on Mac OS X which uses libedit instead of
readline.

does crash on Mac OS X which uses libedit instead of readline.

ignores BlockingIOError exceptions. Initial patch written by Xavier de Gaye.

Document also in asyncore documentation that recv() may raise BlockingIOError.

BlockingIOError exceptions. Initial patch written by Xavier de Gaye.

Document also in asyncore documentation that recv() may raise BlockingIOError.

not a terminal to not write the ANSI sequence "\033[1034h" into stdout. This
sequence is used on some terminal (ex: TERM=xterm-256color") to enable support
of 8 bit characters.

terminal to not write the ANSI sequence "\033[1034h" into stdout. This sequence
is used on some terminal (ex: TERM=xterm-256color") to enable support of 8 bit
characters.

sentence. Patch written by Saimadhav Heblikar.

Patch written by Saimadhav Heblikar.

Patch by Martin Matusiak.

Avoid cast from (int*) to (u_long*), even if sizeof(int) == sizeof(u_long).

and skip test_win32.FunctionCallTestCase.test_SEH when Python was compiled
in debug configuration or by a non-MSC compiler.

Tkinter methods.