FieldSet::make_output_field_selection() creates selection with description including units.
Merge branch 'output_master' of github.com:flow123d/flow123d into output_master
Updated output for reactions (input key 'output_fields', stream inherited from the parent equation).
- output_fields have default value, so implicitly the results are saved
- fix name of selection for Darcy flow output_fields
- fix description of output_fields selection's values
- updated test con files