Write XML/JSON files, refactoring of settings etc.

- Settings now have a group name to namespace/group them
- Export now writes multiple XML/JSON files with all settings or just some
  groups of settings
- config file format changed a bit to support parameters for the
  implementers of export, report and runner
- adjusted DIST config files for current changes to write multiple config
  files on export
- __class, __group and __name are now "special" parameters (at least
  namewise) to make it easier to transition to XML config file format (and
  use those as attributes instead of parameters)
- adjusted tests to changes and added some for small things