Link the core with CoreServices, not with Carbon, and don't use any Carbon

routines. As of 10.1 using Carbon will crash Python if no window server is
available (ssh connection, console mode, MacOSX Server). This fixes bug
#466907.

A result of this mod is that the default 8bit encoding on OSX is now ASCII,
for the time being. Also, the extension modules that need the Carbon
framework now explicitly include it in setup.py.