Multifield name in output.

-when outputing concentrations (multifield) in mobile and immobile zone, they where written in arrays named by substance named
- so they overwrite each other
- solution: both multifield name and field name is written as the name of output array
DualPorosity output is done.
Destructor in dual porosity - mpi vecs added.
Output in Sorptions like in DualPorosity.

- problem of renaming the output arrays in dual porosity mode NOT solved
Rename immobile concentration matrix in dual porosity.
Rename DualPorosity class.
Sorption output - sovled by renaming substances.
Merge branch 'output_master' into PE-reactions-output.

- outputs in dual porosity a sorption is ready
- output in linear reaction is not available
- all outputs in reactions are 'optional'
- output names are ready to name convention
- new outputs in con files - test20, 23 are commented, can be enabled easily

Conflicts:
	src/io/output.h
	src/transport/transport.cc
	tests/23_dual_porosity/dual_por.con
Fix - resize output_names_ in SorptionBase before initialization.
Merge branch 'output_master_new' into output_master

Conflicts:
	src/flow/darcy_flow_mh_output.cc
	src/reaction/sorption_base.cc
	src/reaction/sorption_base.hh