Stub modules will be easier to track (and remove) if they are all kept
in lib-old/, instead of sprinkling them throughout the library.

so the tests work when run from an install directory.
They are currently skipped on the daily runs (not from the buildbots)
for checking refleaks, etc.

in r62788.

The new mac-specific functions must be ignored.

which clears them at the end.

This patch removes the dependency on the Carbon package from urllib.
The mac-specific code for getting proxy configuration is now writting in
Python using ctypes and uses the SystemConfiguration framework instead of
InternetConfig. Also provides a mac-specific implementation of proxy_bypass.

The 'mac' platform (that is, os.name == 'mac') was used for the MacOS 9 port,
which is no longer supported (as of Python 2.4 IIRC).