anchor.diff:    /opt/python/bin/pip install git+git://github.com/pytables/pytables@develop
   
   # Install NLTK
  -RUN yum install -y tkinter && \
  -  /opt/python/bin/pip install nltk pyyaml
  +RUN /opt/python/bin/pip install nltk pyyaml
   
   # Create IPython profile, then
   # install MathJAX locally because CDN is HTTP-only
  -RUN mkdir -p /opt/ipython && \
  -  IPYTHONDIR=/opt/ipython /opt/python/bin/ipython profile create default && \
  +RUN IPYTHONDIR=/opt/ipython /opt/python/bin/ipython profile create default && \
     /opt/python/bin/python -c "from IPython.external.mathjax import install_mathjax; install_mathjax()" && \
  -  chown -R researcher /opt/python /opt/ipython
  +  rm -rf /home/researcher/.ipython
  +
  +USER root
   
   # Add supporting files (directory at a time to improve build speed)
   COPY etc /etc
  
positive.code:   libpng-devel freetype-devel \
    hdf5-devel \
    netcdf-devel \
    libyaml-devel
  
  # Install system-indepedent python environment
  RUN virtualenv /opt/python
  
  # Install from PIP
  # - Notebook dependencies
  
negative.code: # - Readline for usability
  # - Useful IPython libraries
  # - Missing IPython dependency
  RUN source /opt/python/bin/activate && \
    pip install --upgrade setuptools==9.1 && \
    pip install \
      tornado pyzmq jinja2 \
      ipython \
      pyreadline \
  