Rename SWIG "main" module to "cc_main" so it's

Rename SWIG "main" module to "cc_main" so it's
clear from the Python side that this is the
interface to C++.

src/SConscript:
    main_wrap.cc -> cc_main_wrap.cc
src/python/SConscript:
src/python/m5/__init__.py:
src/sim/main.cc:
    s/main/cc_main/
src/python/m5/config.py:
    s/main/cc_main/
    Also directly import cc_main so we don't need
    to put the "m5." in front all the time.

--HG--
extra : convert_revision : 755552f70cf671881ff31e476c677b95ef12950d