2016-11-21: manually upgraded cuDNN to 5.1 for Cuda 7.5
            don't understand why there are two installation on MAC OS. One in
            /usr/local/cuda, the other in /Developer/NVIDIA/CUDA-7.5
2016-11-25: need k-means
2016-11-28: to remove installed packages
            python setup.py install --record files.txt
            cat files.txt | xargs rm -rf
2016-12-08  uploaded to pypi with ``twin upload dist/*``
