Merge pull request #2426 from TomFischer/UseMPLInHT

Applications/ApplicationsLib/ProjectData.cpp

...process/HT/thermal_dispersivity/i_thermal_dispersivity.md

...ocesses/process/HT/thermal_dispersivity/t_longitudinal.md

...rocesses/process/HT/thermal_dispersivity/t_transversal.md

ProcessLib/HT/CreateHTProcess.cpp

ProcessLib/HT/CreateHTProcess.h

ProcessLib/HT/HTFEM.h

ProcessLib/HT/HTMaterialProperties.h

ProcessLib/HT/MonolithicHTFEM.h

ProcessLib/HT/StaggeredHTFEM-impl.h

Tests/Data/Parabolic/HT/ConstViscosity/square_5500x5500.prj

...nthetics/CoupledPressureParabolicTemperatureParabolic.prj

...CoupledPressureParabolicTemperatureParabolicStaggered.prj

...ata/Parabolic/HT/SimpleSynthetics/IsothermalFluidFlow.prj

...olic/HT/SimpleSynthetics/IsothermalFluidFlowStaggered.prj

...ic/HT/SimpleSynthetics/IsothermalFluidFlowWithGravity.prj

...pleSynthetics/IsothermalFluidFlowWithGravityStaggered.prj

...impleSynthetics/PressureDiffusionTemperatureDiffusion.prj

...hetics/PressureDiffusionTemperatureDiffusionStaggered.prj

...impleSynthetics/PressureParabolicTemperatureParabolic.prj