RapidSMS app for growth monitoring:
    - register health workers / survey team members
    - keep track of patient data over time
    - instant statistical assessments based on WHO standards
    - available in English and French
    - currently implements registration, so disable rapidsms.contrib.regsistration

Depends on people app:
    https://github.com/ewheeler/rapidsms-people-app

Depends on pygrowup library:
    http://github.com/ewheeler/pygrowup
        or
    pip install pygrowup

uses pygrowup to calculate z-scores for the following anthropometric indicators:
    weight-for-age, length/height-for-age, and weight-for-length/height
based on the WHO Child Growth Standards:
    http://www.who.int/childgrowth/standards/en/
    http://www.who.int/entity/childgrowth/standards/technical_report/en/index.html