Add COPYING.txt file

This file includes all relevant licensing information for source and
binary distributions of cern-cpymad.
Bootstrap dependency on setuptools in setup.py

Including and using ez_setup.py is the officially recommended way to
make sure setuptools is available (though not necessarily installed)
during installation. See:

https://pypi.python.org/pypi/setuptools/5.7#installation-instructions
Rely on setuptools to set up the namespace package

setuptools is a dependency anyway, so it's fine to fail in case it's not
available.
Include ez_setup.py in source distribution
Fix problem with pip and ez_setup.py
Merge pull request #86 from coldfix/bootstrap-setuptools

Bootstrap setuptools installation
Merge pull request #84 from coldfix/add-madx-license

Add MAD-X license information