Updates to mpeds Dockerfile

[cmball1]

Issue: Could not build mpeds Docker image most likely due to old version of setuptools. Failed to install python requirements, specifically nltk.

Collecting pandas==0.20.1
  Downloading pandas-0.20.1-cp27-cp27mu-manylinux1_x86_64.whl (22.3 MB)
Collecting numpy==1.12.1
  Downloading numpy-1.12.1-cp27-cp27mu-manylinux1_x86_64.whl (16.5 MB)
Collecting nltk==3.4.5
  Downloading nltk-3.4.5.zip (1.5 MB)
    ERROR: Command errored out with exit status 1:
     command: /usr/bin/python2 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-ofx8sl/nltk/setup.py'"'"'; __file__='"'"'/tmp/pip-install-ofx8sl/nltk/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-zXcH6h
         cwd: /tmp/pip-install-ofx8sl/nltk/
    Complete output (1 lines):
    error in nltk setup command: 'install_requires' must be a string or list of strings containing valid project/version requirement specifiers
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
ERROR: Service 'mpeds' failed to build : The command '/bin/sh -c pip install -r requirements.txt' returned a non-zero code: 1

Changes:

• Use LABEL maintainer= in place of the depreciated MAINTAINER
• Install requirements to build python from source
• Install python 2.7.10, the version specified in the publication
• Update pip and setuptools