gituser/pypi: links for pymath-stable

gituser/pypi PyMath-Stable-0.0.20.tar.gz
gituser/pypi PyMath_Stable-0.0.20-py3-none-any.whl
gituser/pypi PyMath-Stable-0.0.16.tar.gz
gituser/pypi PyMath_Stable-0.0.16-py3-none-any.whl
gituser/pypi PyMath-Stable-0.0.15.tar.gz
gituser/pypi PyMath_Stable-0.0.15-py3-none-any.whl