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
Documentation reaction term introduction added.
Merge branch 'output_master' of https://github.com/flow123d/flow123d into PE-reactions-output
Record substances moved to SorptionBase (not needed in DualPorosity and chemistry).
Renaming fields in DualPorosity.
Renaming fields and others in Sorption.
Rename Reaction base class, introduce reaction_term.
Renaming por_m to porosity.