A new module and command-line tool that take a Franca IDL model as input and generate documentation in some form, based on the AST and structured comments.

Potential output format options are:

• Sphinx - appropriate for Python environments
  • the AST can be converted to reStructuredText, similar to a Breathe renderer
  • a docutils node tree can be generated directly from the AST
• Doxygen through OMG-IDL, similar to this implementation - Test and improve doxygen filter. franca/franca#141
• other suggestions?