Step 1 in packaging the toolbox modules and making MacPython more

like normal Python. toolbox modules are now in the Carbon package
in :Mac:Lib, with a workaround flat namespace in :Mac:Lib:lib-compat.
Other dynamic modules are in :Lib:lib-dynload. :Mac:Lib:lib-toolbox and
:Mac:Plugins are gone.

Mac/PlugIns/readme.txt

-This folder contains the dynamically loaded extension modules for MacPython.