Merge pull request #2804 from endJunction/RichardsMechanicsMassBalanceBasedPorosity

...erty/PorosityFromMassBalance/c_PorosityFromMassBalance.md

...es/property/PorosityFromMassBalance/t_initial_porosity.md

MaterialLib/MPL/CreateProperty.cpp

MaterialLib/MPL/Properties/CreatePorosityFromMassBalance.cpp

MaterialLib/MPL/Properties/CreatePorosityFromMassBalance.h

MaterialLib/MPL/Properties/CreateProperties.h

MaterialLib/MPL/Properties/PorosityFromMassBalance.cpp

MaterialLib/MPL/Properties/PorosityFromMassBalance.h

MaterialLib/MPL/Properties/Properties.h

MaterialLib/MPL/Property.cpp

MaterialLib/MPL/Property.h

ProcessLib/RichardsFlow/Tests.cmake

ProcessLib/RichardsMechanics/LocalAssemblerInterface.h

ProcessLib/RichardsMechanics/RichardsMechanicsFEM-impl.h

ProcessLib/RichardsMechanics/RichardsMechanicsFEM.h

ProcessLib/RichardsMechanics/RichardsMechanicsProcess.cpp

ProcessLib/RichardsMechanics/Tests.cmake

...Data/RichardsMechanics/deformation_dependent_porosity.prj

...eformation_dependent_porosity_pcs_0_ts_107_t_3.500000.vtu

...eformation_dependent_porosity_pcs_0_ts_112_t_4.000000.vtu