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

Content-Length header.  Patch by Antoine Pitrou.

fromlist which causes its own ImportError (e.g. the module tries to
import a non-existent module) should have that exception propagate.

The doctest examples that illustrate the use of doctest option flags
independent of doctest directives should not display doctest directives.

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

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

This changeset also applies the rendering workaround to the last remaining
example in the file that has a doctest directive that should be displayed.

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.

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.