1 2014-04-23
    First Version

2 2014-04-29
    Encode perl data into JSON String

3.01 2016-01-12
    - print out the json in full
    - the --env set default to "payload"
    - scripts will use the "exported payload" environment variable
    - flat down levelized json with "print_variables --flat" argument
    - use eval $(print_variables) to export all key-value into current session