Fix issue #16270: urllib may hang when used for retrieving files via FTP by using a context manager.

Patch by Todd Rovito.

Thanks to Yongzhi Pan from docs@

Reported by: Roumen Petrov

Original patch by Felipe Cruz.

Specifically, make sure the 'Object', 'Python' and 'Include' directories
in the build directory take precedence over the source directory if we're
an out-of-tree build.

Fix typeslots.inc so that it gets generated into the build directory.

This change includes replacing the single-line signature documentation
with a more complete multiple-line signature.

Add handling of the 6.2 release line, aka Windows 8 and Windows 2012 Server.

Issue #12947: revert earlier workaround and use a monkey-patch to enable showing doctest directives only in the doctest docs.

misleading error message stating that args[0] did not exist when
either the cwd or executable keyword arguments specified a path that
did not exist.

It now keeps track of if the child got as far as preexec and reports it if
not back to the parent via a special "noexec" error message value in
the error pipe so that the cwd can be blamed for a failed chdir
instead of the exec of the executable being blamed instead.

The executable is also always reported accurately when exec fails.

Unittests enhanced to cover these cases.

Patch by Berker Peksag.

Patch by Chris Jerdonek. Address Ezio's review comment.

Issue #16115: Improve subprocess.Popen() documentation around args, shell, and executable arguments.

Done with great native-speaker help from R. David Murray.

This commit rewrites the docstring for int() to incorporate the documentation
changes made in issue #16036.  It also switches the docstrings for int(),
str(), range(), and slice() to use multi-line signatures.

Patch by Arne Babenhauserheide.