[mpnc][reference] change reference solution for evaporation. The difference to...

[mpnc][reference] change reference solution for evaporation. The difference to the old solution is this:
*harmonic mean for diffusion coefficients
* change in boundary conditions, no outflow, only inflow from left, no dirichlet for temperature
* changed input values for sw_initial so that more diffusion takes place over the interface of pm and ff