ProFormA format

converts ProFormA tasks into proforma programming quiz questions.
This question format is needed by the question type ProFormA.
Supported ProFormA version: 2.0 ( https://github.com/ProFormA/proformaxml )
ProFormA version 1.0.1 is also covered but will no longer be maintained.
Limitations:
reads only zip files containing a task.xml file
embedded bin files and attached text files are not supported
submission restrictions: regular expressions are not evaluated