Add python 2

base/python:2

+FROM python:2.7.15
+ MAINTAINER Tamas Gal <tgal@km3net.de>
+
+ RUN apt-get update -qq && apt-get install -y -qq libhdf5-dev
+
+ RUN pip install -U pip setuptools wheel
+ RUN pip install numpy
+ RUN pip install scipy pandas sklearn statsmodels numba numexpr tables h5py
+ RUN pip install pytest pytest-cov docopt sphinx sphinx-gallery
+ RUN pip install matplotlib seaborn pillow ipython jupyter notebook pillow