Add setup.py for setuptools installation.

$ python setup.py build
$ python setup.py bdist_egg; ls -l dist
$ sudo python setup.py install
Fix the sketchy shellcode in setup.py.

On some platforms (e.g. OSX) cp -pr * ./x will copy x to x recursively,
resulting in a limited but offensive depth of recursive redundancy.
This changes the shellcode to avoid that pitfall, without actually using
nice python code for it.
ignore build directory from setuptools