execfile().

Closes #15281, #15283: Don't make venv scripts executable, but copy source mode instead, and provide better help for pyvenv.

Issue 14814: The new systematic tests aren't just about error reporting any more - change names accordingly. Added and tweaked some example to ensure they were covering the intended code paths

issue 14826 - Address the buildbot failure quote of url is the required change ( explanation msg164973)

Patch by Brian Brazil.

Patch contributed by Stephen Thorne.

Patch contributed by Stephen Thorne.

Fix 5931 - Python runtime hardcoded in wsgiref.simple_server - Now it specifies an implementation specific term.

earlier without preceding space.

The leak occurred by setting:
echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6
before running test_support.

Patch by Brian Brazil.